Product Description: •Type : Red and Green Dot •Material : High Grade Aluminum Alloy •Rail system : 11 & 20mm •Length : 96mm •Weight : 280g •Magnification : 1x •Objective Aperture : 36 mm •Powered by : 1x CR2032 batteries (Included) •Package Content : 1 x Red Green Sight Scope 1 x Cleaning Cloth 1 x Instructions 1 x Wrench Feature: • Black aluminum body • Constructed from aluminum alloy with anodized matte black processing • Light weight and compact design • Anti-glare reflective coated lenses that gives good optical clarity • Dot Color: Green / Red • Adjustable brightness and elevation • 5 Level Brightness Control • Compatible for 10mm and 20mm scope rail mounts (standard) • Integrated weaver style mount Warning: •Please noted that the red dot can only used for hunting and airsoft,not suitable for real gun. Q&A Question: How do you remove and replace the batteries? Answer: On top of "Light switch" it has 3V 2032 battery inserted, if you try to unscrew "top roof" of metal you will see. Question: Does this red dot scope fit a weaver or a picatinny base? Answer: Picatinny. Question:What is the battery size for a red dot Answer:Per the description "3V lithium battery (CR2032)" . Question:Does it have magnification ? Answer:No magnification. Question:Will this fit on a H&K G36 airsoft gun? Answer:It should if you have picatiny rails.