Specification :

Sockets come in 6, 8, and 12 points and 1/ 4" , 3/ 8" , 1/ 2" , and bigger drives. The points refer to the way the socket grips the bolt or nut. 6 and 12 point work on hex head bolts and nuts. The 6 point has a very strong grip on the hex head. the 12 point has a weaker grip but allows the socket to go on the bolt easier. I always try to get 6 point sockets. I don' t think the 12 point are that useful. The drive refers to the square that is used to drive the socket. 8 point sockets are used on the square nuts seen on farm machinery. You will need sockets in the same sizes as your wrenches. Sockets below 10mm will use 1/ 4" drive handles. 3/ 8" drive goes from 10mm up to 19mm. 1/ 2" drive goes from 10mm on up to 36mm or so. 3/ 8" seems to be the drive to use for most bike work.