Tri-Rails Barrel Mount 1, Mount Rail Fit Remington Mount 2, Fit from Dia 25-45mm 3, Full Metal 4, Picatinny rail Specifications: 1. Dia: from ... caliber or air rifle gun 6. Triple 21mm picatinny and weaver rails with 5 slots 7. Fit on Remington etc and ... , grip, flashlight and bipod etc Funpowerland Remington Tri-Rails Barrel Mount