The Proto J7221M 3/8-inch drive impact socket is engineered for use with impact wrenches and air tools, delivering reliable torque transfer in demanding industrial, automotive, and MRO applications. The 6-point design maximizes contact on fastener flats, reducing rounding and improving grip on tight or corroded fasteners.
Built to Proto's professional standards, this 21mm metric impact socket is a durable addition to any mechanic's or technician's socket set, suitable for production lines, maintenance facilities, and heavy-duty repair work.