DescriptionModel Number : Spirit Bubble LevelGuide Length : 10"/25cmGuide Type : RollingOrigin : Mainland ChinaMaterial : PlasticFor : 20MM/11MM Picatinny Weaver RailFeature : Scope Level Tool,Riflescope tube,Sight Scope Mount Adapter,Spirit Level Balance Pipe,Bubble Level Anti Cant,Airsoft Gun Tube Balance,Hunting AccessoryHunting Spirit Bubble Level for 11mm/20mm Picatinny Rail Rifel Airsoft Scope Leveling Tool Kit Hunting Optical Mounts AccessoryFeatures:Anit-cantmake sure your scope is absolutely level.Easy to usequickly and easily level your optics in the field, at the range, or at homeSmall sizefor convenient storage and transportShock resistantCan be used on real fire caliber as well as air rifles.For rail mountCompatible for 20mm/11mm lead rail, can be installed quickly and easily for rail.Note: Attaches directly to weaver/picatinny dovetail to ensure bore and reticle alignment at a glance, and can be place before, after, or under the scope.Specifications:Material: plasticColor: Black20mm Type :Size: 57*11*11 mmCompatible for 20mm lead rail11mm Type :Compatible for 11mm lead railPackage Includes:1 X Spirit Bubble Level