I've seen pedals which take a hex key, but never one that takes a hex socket. What have you seen?Where the pedals are thus equipped, a 6mm hex socket and undo them from the rear side if the crank.
I'm not sure that the ebay listings of "Shenzhen aBigjoy Technology Co., Ltd" are the most authoritative users of English you could have appealed to - and even they hedge their bets calling them hex key bit sockets in an almighty linguistic pile-up