Product Details:ded by pulling from 13.5cm to 15cm1.Fit Picatinny and Weaver Rail2.Fit Barrel with adapter3.Height (from top mount base to foot bottom): From 120mm to 140mm (5.0 to 6.0 inch) with various adjustment4.Weight (net): 260g5.Easy use and installation6.Release and press down the button to fold the feet7.Release the feet screws to extend the length8.Rubbber Feet avoid slip9.High durability aluminum alloy in black matt and beautiful complement10.Can be used on real fire caliber