870 Stock Bolt, 10.5" or 8.5"
Remington OEM Stock bolt. 10.5" fit all Standard Remington stocks. 8.5" fits 20ga Jr. 12" LOP stock.
Note if you need washers simply get them at the Hardware store as the Remington ones are at the minimum parts cost of $4.37 each and are simply washers. You will need one large washer and one lock washer so look at the ones you have and match them.