Red Dot Scope with Messer Optic Bow Sight Mount Fits All Compound Bows Tubeless design with 33mm reflex lens aperture provides a wide field of view. Multi-reticle (adjustable 4 different sized red dots) are installed. Automatic Brightness Control setting. 8 manual brightness level adjustment. Parallax free and unlimited eye-relief. Very lightweight; waterproof and shockproof. All with low power consumption