This Master Mechanic socket adapter set includes four pieces, with one 3/8″ and three 1/4″ adapters. The hex/allen drive type and black oxide surface finish make these adapters durable and reliable for any job. The set is brand new and comes from China, with the manufacturer part number 1-158716 and 3-504803. The adapters are perfect for standard socket types and come in a set rather than as single items. The drive size is 1/4″. 4 TOTAL PCS PACKAGED INDIVIDUALLY 3- 1/4¨ & 1- 3/8¨ = 4 TOTAL