It looks like a giant rubber zip, and it sort of is. It does however perform perfectly as a jar opener. Those slippery awkward jars can now be opened easily, jars of pickled onions will no longer become part of the scenery sitting quietly at the back of the cupboard.
Just tighten the Zip Eat Jar Opener over the lid of the offending 'stuck' jar, give a slight squeeze and a turn and the jar should easily open. Should the jar not open just return it to the back of the cupboard and wait for the next ingenious kitchen gadget to be invented that claims to open jars in a few years time.