Material: 100% PEVA. Fully waterproof and reusable — this is not a one-use emergency sheet. Hood, snap-button closures down both sides, and a carrying bag. 50 in. x 80 in. (127 x 203 cm), one size fits all.

The side snaps are the difference between a poncho and a bin bag. Snapped shut it is a garment that stays on you in wind; open, it vents, which is how you avoid being just as wet from the inside.

Fifty by eighty inches covers you and a day pack. Over a loaded rucksack it is the only rain layer that does not need its own rain cover.

PEVA rather than PVC: no chlorine in it, and it stays flexible in the cold instead of going stiff and cracking at the folds.

Packs to nothing in its bag. Keep one in each vehicle and one in each pack — this is a thing you own so you never have to decide whether to bring it.