Nikon AP/ AC/ AX Series auto levels are compact and lightweight— they weigh just 2.8 lbs— making them convenient and easy to use in the field. Their rugged, water-resistant construction means you can use them in light rain or dusty conditions. AP/ AC/ AX Series auto levels are easy to set up and easy to use. All three models can attach to both flat- and spherical-head tripods, and horizontal tangent knobs with an unlimited range ensure smooth, precise pointing and angular measurement-and you can operate them with either hand.