HEATLOCK B1 Emergency Bivvy

Most emergencies that turn dangerous don't start with a disaster. They start with a stalled car on a closed highway, a power outage that runs into the second night, or a hike that takes longer than the daylight. The cold is what turns an inconvenience into a problem, and the thing that fixes it has to already be with you.

The HEATLOCK B1 Emergency Bivvy is heat-reflective film made into a bag, and that is exactly why it fits in a glovebox. It fits adults up to 6'4": it unfolds to nearly 7 ft, longer than a twin mattress, so you can climb all the way in with your clothes on and pull it up to your shoulders. Packed in its drawstring sack it's about 2.6 x 3.9 inches, about the size of a standard soda can, and the whole kit weighs 4.6 oz, about as much as a smartphone. It goes in the glovebox, the go-bag, the day pack or the desk drawer and stays there until the night you need it.

The inside is a silver aluminized lining that reflects the heat your body is already making back toward you. The outside is a sealed PE outer layer with sealed edges, so you're wrapped in a closed bag instead of fighting a flat blanket that blows open. Get in, pull it up to your shoulders and hold the opening closed around you, and you can feel your own heat staying with you. At home it also works as an extra layer: slide it over your blanket or sleeping bag.

Pick the color for where it will live. Orange is for the car and the trail, where being found matters: it stands out against snow, rock and roadside brush. Army green is for the home kit and the evacuation bag, when you'd rather stay low key. Both have a rescue whistle tied on the end of the drawstring, so it's in your hand when you need it.

One per car. One per go-bag. One per adult in the house. Small, light cold-weather insurance that is ready when the heat isn't.

Product: HEATLOCK B1 Emergency Bivvy (thermal emergency sleeping bag)
Material: aluminized PE film (PE + aluminum foil composite, silver reflective inner surface)
Unfolded Size: 210 x 90 cm (82.7 x 35.4 in), fits adults up to 6'4"
Packed Size: about 6.5 cm diameter x 10 cm tall (2.6 x 3.9 in) in the stuff sack
Weight: 130 g (4.6 oz) for bag, stuff sack and whistle
Edges: sealed edges
Colors: Orange, Army Green
In the Box: 1 emergency sleeping bag, 1 drawstring stuff sack with cord lock, 1 rescue whistle tied on the drawstring
Suggested Storage: glovebox, go-bag, backpack, emergency kit
Safety: Not a toy. Keep away from infants and small children and never let a child use it alone. Keep your face uncovered and never close the bag over your head. Keep away from open flames and heat sources.