Cr-V alloy steel with satin chrome finish sockets. Master set includes: Shallow and deep sockets in sizes 4mm to 15mm and 3/16" to 9/16", a Pro 10" 90-Tooth 1/4" Dr. Heavy Duty ratchet, two extensions, a spring loaded crowfoot wrench and a spring loaded universal joint. Conveniently packed in EVA foam to fit directly into your toolbox drawer.