The Sentinel combines the traditional Yukon style of perfect design, ergonomics, reliability and easy and convenient use with an enhanced level of functionality. This incredible sight has a high IPX4 grade of water-resistance and can be operated in extremely precipitous situations while functioning normally and without causing damage to the unit. Extra tube protection provides durability towards the axial load when used with the majority of popular calibers. The 2xAA batteries are placed in the battery compartment vertically, thus eliminating the influence of recoil on the stability of the energy supply. The Sentinel has two scales, a horizontal scale to measure the distance to a target and a vertical scale. Multiple Reticle colors can be changed by the simple push of a button.