This is the locking pin set for the m38 cavalry carbine Carcano rifle, also will fit the older m91 cavalry carbine, folding "SPIKE" bayonet style. This seems to be a very common item that needs replaced because it is often broken or missing. There are 3 pieces: screw, nut and spring. These are new-made, from an original sample in detail.
Screw and nut are made of quality medium carbon steel with all details present. The spring is new and not exact to an original, but it fits and works correctly. This spring is stronger, which actually helps lock in better (an upgrade from the original). All parts hot process black oxide treated for long life and will hold their finish.