Product Specification Material: Aluminum Alloy Product Weight: 20 g Product Size: 50 x 21 x 9 mm Package Weight: 52 g Package Size: 85 x 65 x 40 mm -made of aluminum alloy, which is very durable and has excellent quality. It can be used as an extension accessory. -It uses a 3/8" screw for mounting accessories, and there are two locating pins beside the screw to help fix it and prevent the screw from loosening or position deviation. -A good extra accessory for mounting, easily to attach other accessories with NATO Rail.