Hawke Sport Optics Vantage 4-12x40 AO 17HMR IR Riflescope 14241 11- layer fully multi-coated optics for&nbsp;excellent clarity. Adjustable objective for parallax&nbsp;correction (AO) models. 1" and 30mm mono-tube chassis for&nbsp;superior strength. Glass etched reticle with red and&nbsp;green illumination. Rheostat on saddle offers (5) levels of&nbsp;brightness.