HOLOSUN Paralow HS403D Micro Red Dot Sight (2 MOA) with Battery Housing on LEFT, New LED technology allows 50,000 hours of operation on one battery. Auto-On with Movement and Auto Shut-Off after 8 hours. (Also has Manual Off) Battery housing on LEFT side of optic provides easy access to battery and better for left handed shooters. Parallax-free; when the red dot is on the target, so are you; 2 MOA dot size High quality, clear lens with crisp, bright red dot Fully waterproof IP76 and submersible to 3 meters for 30 min.; High strength aluminum, MAO finish; LIFETIME WARRANTY