Ultimate Arms Gear M1 M-1 Carbine Rifle Precision Steel Matte Peep Aperture Rear Sight Assembly Adjustable Windage and Elevation Fully Adjustable for both Windage and Elevation, and is a modern-day recreation of the Original, WWII-Era Milled Adjustable Rear Sight that blends an authentic appearance with exceptional functionality. Wire-EDM machined from 4140 Chrome Moly Steel that is then heat treated to a hardness of RC 38-40, and features precise click-adjustments for windage that produce reliable, consistent point of impact changes. Elevation adjustments are accomplished by sliding the Peep Aperture Ramp forward or rearward to engage one of the four different detent positions (Marked "1," "2," "2.5," and "3" indicating the range to the target). Material: 4140 Chrome Moly Steel. Blade Type: Peep Aperture (0.085" Dia). Elevation Adjustable: Yes, Ramp w/4 Pre-Set Range Settings. Windage Adjustable: Yes. Reproduction of WW-II Era Milled Adjustable Sight. Fits M1 Carbine.