The “extra bavet” is an extra bib for the front of your suit pants, and the shoulder straps attach to the top of it instead of to the waistband of the pants.  It has been described humorously (and pretty accurately) as follows: “The extra bavet suit pants are almost like overalls for your suit. The little extra flap helps to protect your belly in case you have an extra vengeful dog who just needs to bite your stomach. Or you have a dog that somehow manages to get up under your jacket. In any case, the extra bavet will help make sure your belly stays wound free.”