M1/M2 Carbine Barrel Band Retaining Spring
I'm making a follow-up comment. This spring doesn't even work. The nub isn't big enough to protrude through the barrel band hole. Waste of money.
The spring design is not even close to the original and does a very poor job of securing the hardware to the stock. I will have to use the original
The photo would give you the impression that you will get a used USGI spring. What I got was a new aftermarket one which has a shiny black finish like powdercoat. OK for me because the M1 carbine is going in a modern polymer stock, but if you are looking for USGI be warned.