The EOTech® Model 512TM XBOW, Crossbow Holographic Weapon Sight combines the lightning-fast target acquisition of a heads-up sight with the ease and convenience of a pre-calculated ranging scale and ranging dot reticle. With both the range information and aiming reticle displayed in the same sight picture, you can quickly line up a shot with a minimum of movement and noise. And less movement and noise often translates to greater success. Simply position the base of the scale on the belly of the deer at which you're aiming, then read where the deer's back intersects the scale and you have your distance. An easy to dial ballistic calculator shows distance based on the fps of your crossbow in relation to the 4-dot reticle.