1/4″ & 3/8″ Drive 12 Pt. Standard & Deep Mechanics Tool Set, SAE/Metric. 90-tooth gear delivers a 4° swing arc to turn a fastener in tight confines. Sockets feature off-corner loading design to reduce fastener rounding. Mechanics tools have all been designed with the professional user in mind to increase productivity, access, and strength. The ratchets and sockets are made from premium alloy steel and feature a full polish chrome finish that resists rust and corrosion. Large, hard-stamped markings allow for easy identification and can be easily recognized as SAE (double line) or metric (knurled line). Additionally, the off-corner loading design puts force on the flats of fasteners for improved durability and reduced fastener rounding.