This Primus windshield features a sprung construction that allows it to clip directly onto virtually all self sealing gas canisters. The windscreen not only screens the wind, but also improves your stoves efficiency by directing heat up the sides of the pot, so you use less fuel, so you dont need to carry as much, so your pack is lighter. When your done cooking the windscreen can be stored over the top of the canister. An awful lot of design genius has gone into something so simple.