What is "ring-pull"

Usage examples of "ring-pull".

An expert trav­eler could get by on some ring-pulls and self-heats that he raided or traded for in arid country.

A few seconds later she found another door, which led to a bathroom and a provisions area stocked with self-heats and ring-pulls of water.

As much ammo, self-heats and ring-pulls as is safe to carry if we have to move fast and quiet.

They'd been unable to find anything worthwhile and had been forced to rely on the self-heats and ring-pulls they were already packing.

We're almost flat out of self-heats and ring-pulls, and if we can't eat and drink when we need to travel light and quiet for a while, we're in trouble.