The PARALOW HS403A Red Dot scope has no external battery housing. The battery is hidden in the base where is will rarely need to be changed. This elegant design allows the scope to be simply a tube, allowing the maximum field of vision. Aiming with both eyes is now just a reflex and allows you to have maximum situational awareness. This sight includes 50,000 hour battery life, is parallax free, and has a durable PEO/MAO finish. Add to this an auto wake feature that automatically turns on the scope when it is moved and an adjustable 8 hour auto-shutoff. This scope comes with two mounts, a low profile and a AR height lower 1/3 mount.