Sims Limbsaver AirTech Slip-On Recoil Pad -AirTech Slip-On pads are designed to slip over existing firearm stocks without any modifications. Though slip-on pads will work with or without factory recoil pads, we highly recommend removing the existing pad before putting the slip-on recoil pad on; this will ensure the best fit and will prevent slipping during use. Small: 1" LOP 4-1/2" x 1-1/2" up to 4-13/16" x 1-5/8"Medium: 1" LOP 4-13/16" x 1-5/8" up to 5-1/8" x 1-3/4"Large: 1" LOP 5-1/8" x 1-3/4" up to 5-3/8" x 1-7/8"