Remington R3 Recoil pad for Remington Synthetic Stocks.
This is a proprietary pad made for Remington by Limbsaver. This is a top of the line recoild pad and featured on Remington 870 Police models and some other models. It is recessed so it snaps right into your Remington Synthetic stock. Fits recessed end 12ga Remington Synthetic 14" LOP Stocks for 870, 1100, 11-87 and some others. This is Part number F300820 on the Remington parts list and retails for $46.63. Your existing recoil pad screws will work with the pad so you do not need new ones, however, if you want them they are listed here in this category.
To make sure this is the pad fits your stock look at the second picture. If your Remington stock is recessed like in the picture this is the pad you need.