Proxxon industrial 29 piece socket set for heavy duty mechanics proxxon 23000 this 29 piece socket set from proxxon industrial has a frac12 in 12 5mm square drive and a range of sockets from 8mm to 34mm socket as well as deep sockets for protruding bolts plus 16mm and 21mm spark plug sockets proxxon industrial 23000 socket set for heavy duty mechanics 1 2 29 piece