11 layer fully multi-coated optics for excellent clarity. 1 inch mono-tube chassis for superior strength. Nitrogen-filled and O-ring sealed to be water and fogproof. 0.25 MOA low profile no-snag fingertip turrets. Fast focus eyebell and high torque zoom ring. Threaded objective & ocular for optional accessories. Threads on the ocular and objective provide a solid mounting point for optional accessories such as sun shades.