Adam ... wherever you are 1/4" 3/8" 1/2" and (if you play with big toys) 3/4" are the standard ratchet fitting sizes ... it's a historical thing and now it's in place would be a nightmare to change ... one of those oddities that has absolutely no impact on anything as long as everyone keeps doing it .... you just use your metric or imperial sockets without giving the little square bit a second thought 🙂
K
