This is a knife bayonet originally manufactured as a Model 1938 "Folding" Knife Bayonet. It could be folded - as with a pocket knife - while on the firearm, but not while in the scabbard. The folding mechanism was somewhat fragile, costly, and impractical for combat use, therefore it was discontinued on later variants of the 1938. There were three known variants: folding, fixed-folding, and fixed. The first variant was the true folding original; the second was the folding model where the folding mechanism was made inoperative while retaining the slot in the hilt where the blade folds into; the third was manufactured entirely as a fixed bayonet and does not retain the slot. The later two types utilized a crossguard with a lower quillon.