5/16 Inch Long Fixed/Flex Head 12-Point Ratcheting Box End Wrench Quantity:1 and the tightly mated fit

and the tightly mated fit results in a bit that won't loosen over time or under stress

Radiused corners in the box ends apply force to a fastener's flat sides

Part Number: BIT-DWDRSD1-19/64

1/2"-13 18-8 (304) Stainless Steel Hex Cap Screws

5/16 Inch Long Fixed/Flex Head 12-Point Ratcheting Box End Wrench Quantity:1 and the tightly mated fitOne Wrench Size, Two Head Styles The double box ends are the same size and both are 12 point, but one side features a raised fixed head while the other has a ratcheting flex head Versatile Fixed Head The fixed box end has a flush side to maximize surface contact with a fastener as well as a raised side for finger clearance and to fit into recessed areas Ratcheting Flex Head The ratcheting end reduces the need to re engage the fastener repeatedly, and