The clicks of the front and rear sight are calibrated for 1 MOA (3 cm at 100 m), allowing for a wide vertical and horizontal range of adjustment (240 cm at 100 m) and easy sighting-in of the scope. These sights require no batteries and thus are always ready for use. Corrosion-resistant Mil-spec materials and raised sides protecting the ghost ring and front sight from impact damage ensure many years of trouble-free service. ERATAC Backup-Sight w/Solid Steel-Post