Knurled ends provide grip surface to pull sockets off ratchets. Large hard stamped part number and size on both sides of socket for easier visibility to socket size. Packaged in patented slide rail for easier positioning of sockets - internal slide rail eliminates interference / ball bearing retention. Entry angle guides fastener. Made of 6130 Alloy steel and full polish nickel chrome plated13 Piece 1/2" Drive 6 Point Standard Metric Socket Set includes 12-24mm Standard Sockets packaged on a clip rail. Entry angle guides fastener. Serrated depth as deep as the fastener. Large hard stamped identification. Knurled line to easily identify SAE vs. metric sockets. Made of 6130 Alloy steel and full polish nickel chrome plated.