Optical Acrylic and CNC aluminum Compatible with Picatinny rails High performance and optically clear Compact and low profile design sights have been tested by 1000 plus BBs to ensure complete protection. In the Box 1X BB Proof Lens Specifications: Brand Speed Airsoft Build Optical Acrylic and CNC aluminum Compatibility Picatinny Top Rail Mounts California Proposition 65 Warning: Cancer and Reproductive Harm - www.P65Warnings.ca.gov