This socket bayonet is very similar to the Year IX bayonet. The blade is 15 1/2 inches in length, the socket 2 5/8 9nchs. The bore is 7/8 inch. There re various markings on the shank oand on the socket and blade. A very small mark on the socket reads W over 077. Interesting bayonet in very good condition, withe some darkened areas but no deep pitting. Very clean.