1.AK Ris Rail:Created for placing at the cover of AK receiver. Fits ALL types RIS sights (Holosights, Optic and etc). Installed instead of the regular rear sight. You can still use it as sight on distances up to 300 meters. Includes all what you need to place it at your Airsoft AK. 2.Rail "B-13":This rail created for any AK serie for placing additional optic and holosights instead of basic mechanical scope. This rail working with any AK, which one have Soviet-type optic sight mount.