3/16 Tamper Proof Hex Key Plain (Pack Qty 100) BC-00188KHTP

Designed to be inserted into a like-sized, hollow recess of a socket screw to manually tighten or loosen the fastener Alloy steel containing at least two of the following elements: chromium, nickel, molybdenum or vanadium, in sufficient quantity to assure that the minimum surface hardness meets the standards listed below Sizes through 3/8": Rockwell C 48 minimum. Sizes over 3/8": Rockwell C 45 minimum