Peco Lag Bolt, Measurement System: Imperial, 3/8-7 Thread, 2 in Overall Length, Steel, Zinc Plated, Gimlet Point, 0.226 to 0.268 in H x 0.62 to 0.65 in W Head, 0.36 to 0.388 in Shoulder Diameter, 1/8 in Shoulder Length, Rockwell B70 to B100 Hardness, Hex Head