C & H Research Mercury Recoil Suppressor, Magazine Tube Model. Helps counteract the painful effects of recoil using mercury, one of the heaviest, densest, liquid elements. This mercury recoil suppressor installs within the magazine tube of most semi-auto and pump-action shotguns with a 4-round capacity. Compact, permanently sealed steel case is made from bar stock; the only moving part is the liquid mercury so there's no wear, no chance of leaks. Mercury's viscosity varies only 1% from 0 degrees F. to 90 degrees F. which means the recoil-fighting performance is consistent in almost all weather conditions.Specifications:Finish / Color: SilverFirearm Type: Shotgun,RifleMaterial: Mercury