3/8 Inch Drive x 7/8 Inch Deep 12-Point Impact Socket Tekton they have a slight wedge

they have a slight wedge shape that grips both sides of the slot

but not brittle • Corrosion-Resistant – We coat all of our keys with a durable manganese phosphate finish that’s resistant to corrosion • Clear Markings – Tekton L-key sizes are marked in two ways: with a high-visibility laser marking and a stamped marking

Part Number: BIT-DAM18X9/16

Part Number: EZ-M1016

3/8 Inch Drive x 7/8 Inch Deep 12-Point Impact Socket Tekton they have a slight wedgeSize is marked both with a high visibility laser marking and a permanent stamped marking that won't wear off Deep 12 point socket opening provides an exact fit for 12 point fasteners Radiused corners prevent fastener round off by applying force to a fastener's flat sides, rather than its corners Interior socket well extends far into the socket, which allows for better fastener engagement in more situations Meets a minimum of 1. 3 times the ANSI ASME