Beileshi Red Dot Laser Sight Tactical 20mm Standard Weaver Rail for Pistol Gun Rifle HIGHER ACCURACY: Cross-hair being used instead of the traditional front sight and notch base the aiming speed, accuracy and percentage of hits are greatly increased FIT INTO MOST GUN: The Weaver Rail of Inlook Red Dot Laser Sight is Picatinny 20mm Standard size LONG ENDURANCE LIFE: Its outer covering is made of high - strength aluminium alloy and undergoes special anti-corrosive treatment, and the surface of all the optical spare parts are plated with anti-reflection coating PORTABLE TO TAKE: Its Size is 2.4" x 1.15" x 0.85" or 60mm x 29mm x 23mm.Weight with Battery is 1.65 oz.Voltage: 3 x 1.5v LR44 Batteries CONTACT US: If you have any problem after you receive our product, please fell free to contact us, we will resolve it. Please give us a chance to make you satisfied before you leave a negative review