Buy Shia LaBeouf's Briefs

A seller on EBay is starting the bidding at $400 for a costume – underwear and all – worn by Shia LaBeouf in
“A Guide to Recognizing Your Saints.” The costume, some sweat pants, a pair of briefs and a pair of socks, is being sold “as is,” which presumably means it hasn’t been washed. Swoon away and bid away at
EBay.
Who makes those briefs?