Defender Security E 2293-A Diecast Vintage Lock Bit Key with H-21 Key Number, Zinc Plated The vintage lock Sets that these keys are compatible with are those manufactured by Prime-Line Products, which are designed for interior use only 3/32 in. Thick bit with two inner cuts at 1/16 in. X 5/32 in Zinc Plated finish Diecast construction Key Number H21