What training jammer? Many (Masters)swimmer also wears these to the competition. You won't meet a triathlete without a Funky Trunks jammer. So make sure you always have a pair or so that fits the mood, the locations and goals of that moment. So you are not left with only one jammer, it will last you for years, so you might as well buy a few.

A classic trunk but as a piece of cloth it seems. No fly seam but one piece. Very nice stripe of fabric on the hips. Dear to wear them.