Actually found some at Goodwill a while back. The original ones were very short and had wide leg openings. My first memory of UDTs was a neighbor who was a Navy Seal, washing his truck in a pair. Every time he bent over or stretched his body, his equipment would fall out, and after a while, he just gave up tucking them in until he finished the job. Attached a pic to give you an idea of what I saw that day. He looked like the guy on the right, leg parts slightly rolled up.