HoldFast Thermal Bivvy
HoldFast Thermal Bivvy
Clean drinking water for the whole house when the taps stop. 3.8 litres (1 gallon), no power needed.
The car gives up on a lay-by off the A66 in January, or the tent turns out colder than the forecast promised. Climb in, pull the drawstring, and your own body heat does the work while you wait for the recovery van or the morning.
- Keeps the warmth you already have: the aluminised lining reflects your body heat back at you instead of letting it leak into the night.
- Covers an adult head to toe, 210 cm long and 90 cm wide, with a drawstring opening to close out the draught.
- Weighs about 110 g each and packs down to the size of a mobile phone, so one lives in each door pocket of the car.
- Blocks wind and rain: the waterproof film and heat-sealed seams keep a wet verge or a damp groundsheet away from you.
- Comes as a pack of two in bright orange, each in its own pouch with a whistle, so you can be seen and heard from the roadside.
In the box
- 2 × HoldFast Thermal Bivvy, 210 × 90 cm, orange outside, silver inside
- 2 × drawstring storage pouches
- 2 × whistles on a cord
- 1 × card of folding instructions (how to get it back in the pouch)
Specifications
| Size, open | 210 × 90 cm |
|---|---|
| Packed size | approx. 11 × 8 × 4 cm, in its pouch |
| Weight | approx. 110 g per bivvy |
| Material | aluminised polyethylene film, heat-sealed seams, waterproof and windproof |
| Closure | drawstring opening at the head end |
| Colour | orange outside, silver reflective inside |
| Reuse | yes, if dried and refolded; replace once torn |
Who it's for
- The boot of every car that does a winter motorway, next to the scraper and the jump leads.
- The tent, the bothy and the Duke of Edinburgh rucksack: a warm night's sleep that weighs less than a sandwich.
- The grab bag by the front door, for the night the heating and the power go off together.
Questions
What is the difference between a bivvy and a foil blanket?
A blanket wraps around you and gaps open as you move; a bivvy is a sealed bag you climb into, so the warm air stays in and the wind stays out. For a few hours sat in a cold car or a bus shelter, a blanket does the job. For a night lying down, choose the bivvy.
Does it fit a tall adult?
At 210 cm long and 90 cm wide it takes an adult up to about 1.95 m with the drawstring closed around the shoulders. Two small children fit in one bivvy together, which is often the warmest arrangement anyway.
Can I reuse it after a night out?
Yes. Shake it out, let it dry inside out, and refold it along the original creases; the card in the pouch shows how. It will not go back as small as it came, which is normal. Once the film is torn, replace it: the warmth comes from an unbroken reflective layer.
How long does delivery take?
Delivery across the UK is free. Orders usually arrive in 7 to 12 working days, with a tracking link by email as soon as the parcel is on its way. The HoldFast Promise covers it for 90 days, any reason.
Included free with every kit worth £30
- The Three-Day Larder: a food storage guide and workbook for ordinary British homes (PDF).
- Sensible, Not Scared: the HoldFast guide to a ready home (PDF).
- Free UK delivery
- The HoldFast Promise: 90 days, any reason, full refund
- Apple Pay, Google Pay, PayPal, Visa, Mastercard
Who it's for
Not for preppers. For households that would rather have it and not need it.
A power cut that outlasts the kettle.
Be Ready says mains water can be disrupted during and after a power cut. The bottles go first; HoldFast Wellspring carries on from the water butt or the stream at the end of the road.
A boil-water notice.
Boil every pan, or hang a bag. The cartridge removes the bacteria and parasites most notices are about (the exceptions are in the FAQ).
A burst water main.
A bowser on the next street, shops cleared of bottles by lunchtime. Fill from whatever is to hand.
After a flood.
Filter the silt and the bugs out, then boil or use tablets: floodwater is the one case where we ask for both.
The van, the tent, the Lakes.
No more carrying 20 litres up a hill. A beck and a branch will do.
The allotment and the water butt.
Rainwater off the shed roof becomes a drink on a hot afternoon.
How it works
Fill. Hang. Wait. Pour.
Nothing to pump, charge or squeeze. Hang it higher than your container and come back to clean water.
Fill.
Dip the 3.8 litre (1 gallon) bag in the cleanest water you can find (a running stream over a still pond, the top of the water butt over the bottom) and seal it.
Hang.
Clip the strap to a branch, a cupboard handle, a door frame or a fence post, higher than the container you are filling: gravity needs a bit of a drop.
Wait.
Open the line, let the first cupful clear the air, then leave it. No pumping, no sucking, no squeezing.
Pour.
Clean water fills the collection pouch, a saucepan or, with the adaptor, a bottle. Drink it, cook with it, wash the kids' hands with it. Refill and repeat.
Proof, and the honest bit
What it removes, and what it doesn't
The honest version, because the dishonest one gets people ill.
- Filter: 0.1 micron hollow-fibre membrane, four stages, physical filtration only (no chemicals, no power).
- Removal: 99.99% of bacteria, protozoa and parasites, and microplastics, per the manufacturer's testing.
- Capacity: rated for up to 5,700 litres (1,500 gallons) per cartridge, backflushing permitting.
| In the water | HoldFast Wellspring 0.1 micron hollow fibre | Why |
|---|---|---|
| Bacteria (the usual cause of stomach bugs from untreated water) | Removed, 99.99% | Manufacturer's testing |
| Protozoa and parasites (Giardia, Cryptosporidium) | Removed, 99.99% | Manufacturer's testing |
| Microplastics | Removed, 99.99% | Manufacturer's testing |
| Silt, sand, rust, leaves | Removed (mechanical) | Pore size |
| Viruses | Not removed. Boil or use tablets after filtering. | US CDC: 0.3 micron or smaller removes bacteria and parasites, not viruses |
| Heavy metals, pesticides, fuel, chemical spills | Not removed. Find another source. | Membranes do not remove dissolved chemicals |
| Salt (sea water) | Not removed. | Membranes do not desalinate |
| Floodwater | Filter, then boil or use tablets. | UK Chief Medical Officers: filter, then disinfect |
What it doesn't do
No viruses, no heavy metals, no pesticides, fuel or salt. Floodwater, or anything you suspect of chemical contamination: filter, then boil or use tablets. If you need virus protection, this is not the filter for you, and we would rather say so now than after the 90 days.
Every hollow-fibre filter on the market stops at viruses and chemicals, whatever the price. In Britain, for streams, ponds, rainwater and stored water, bacteria and parasites are what make people ill; that is what this removes.
What's in the box
Everything, and nothing to add
- 1 × gravity bag, 3.8 litres (1 gallon), BPA-free, folds flat
- 1 × 0.1 micron hollow-fibre filter cartridge, four stages, rated for up to 5,700 litres (1,500 gallons)
- 1 × food-grade hose
- 1 × clean-water collection pouch, 3.8 litres (1 gallon)
- 1 × hanging strap with carabiner
- 1 × bottle adaptor (fills a standard bottle straight from the line)
- 1 × cleaning syringe for backflushing
- 1 × storage bag
- 2 × PDF guides: The Three-Day Larder, Sensible, Not Scared
Compared
For the whole household, not a straw
How it compares with what you already have in mind.
| Stored bottles | Boiling | Purification tablets | Filter straw | HoldFast Wellspring | |
|---|---|---|---|---|---|
| Whole household at once | Until they run out | One pan at a time | One container at a time | No, one person, one sip | Yes, 3.8 litres (1 gallon) a fill |
| Hands-free | Yes | No, you watch the pan | Yes, after a wait | No | Yes |
| Works with no power or gas | Yes | No | Yes | Yes | Yes |
| Fills pans for cooking and washing | Until they run out | Slowly | Yes | No | Yes |
| Space it takes | 36 litres for four people, 3 days: 24 big bottles, 36 kg | A pan | A small tub | A pocket | Folds flat |
| Runs out? | Day four | Needs fuel and time | Yes, count the tablets | Rated per straw | Rated up to 5,700 litres (1,500 gallons) a cartridge |
The sensible answer is not one of these on its own. Bottles for the first night, HoldFast Wellspring from then on, and a tub of tablets for floodwater. “Multiple redundancies is best,” as one Mumsnetter put it.
FAQ
The questions people ask us most
How long does delivery take?
Delivery across the UK is free. Orders usually arrive in 7 to 12 working days, and you get a tracking link by email as soon as it is on its way.
Does it remove viruses?
No. A 0.1 micron hollow-fibre filter stops bacteria, parasites and microplastics; viruses are smaller and get through, as with every filter in this family. For streams, ponds, rainwater and water butts in Britain, bacteria and parasites are the realistic risk. If you want virus protection as well, boil the filtered water or use purification tablets after it.
Can I use it with tap water during a boil-water notice?
Yes, with one caveat. Most notices are issued because bacteria or a parasite has been found in the supply, which is exactly what the cartridge removes. If the notice names a chemical problem, the filter will not help. Not sure why the notice was issued? Filter, then boil: it costs you a kettle.
There are bubbles in the line and nothing comes out.
The most common question with any gravity filter, and it is air, not a fault. Hold the hose up so the bubbles rise back into the bag, open the line, and let the first cupful run through. Once the line is full of water it runs on its own. The leaflet has a picture.
Can it freeze?
The bag and hose can. The cartridge must not freeze while wet: ice damages the hollow fibres and you will not see it. Dry it fully before it goes in a cold shed or the boot in winter. Stored dry, frost does no harm.
Is this just a cheap knock-off from Amazon with a markup?
Fair question; we would ask it too. Gravity bags exist at every price. What you are paying for here: a cartridge whose figures we publish, a company that answers emails under its own name, two guides we wrote ourselves, and 90 days to send it back for any reason. If you decide a £15 bag would have done, send it back.
How do I return it?
Email us within 90 days of delivery. We reply with the return address; once it arrives we refund the full price to the card or account you paid with. No “reason” box to fill in.
How long does the cartridge last, and how do I know when it's spent?
The manufacturer rates it for up to 5,700 litres (1,500 gallons), less if you filter silty water without backflushing. It is tired when the flow slows and a backflush no longer brings it back. For a family of four at 3 litres each a day, that is more than a year of drinking water.
What water can I put in it?
Streams, becks, rivers, lakes, ponds, rainwater, water butts, and tap water under a notice. Fill from the cleanest point you can reach. Never sea water, never water downstream of a landfill, a fuel spill or a farm run-off pipe, and floodwater only if you boil or treat it afterwards.
Does it change the taste?
It tastes like the water you put in, minus what you could not see. A peaty moorland stream can still carry a faint tint; that is colour, not a problem. No chemical taste, because there are no chemicals in it.
Will it expire sitting in the cupboard?
No. Stored dry in its bag, the cartridge has no shelf life. Air-dry it after use, pack it away, and check it in October with the torch batteries.
Can the children or my parents use it on their own?
Yes. Nothing to pump, squeeze or suck through. Fill, clip, open the line. A seven-year-old can do the filling; an eighty-year-old can do the hanging. That is why we chose gravity over a straw.
Clean drinking water for the whole house, when the taps stop.
The HoldFast Promise: 90 days, any reason, free UK delivery.
Get HoldFast Wellspring: £89.99, free UK delivery, 90-day HoldFast Promise →