- Features: Anodized precision machined aluminum exterior. Accommodates potentiometer shaft ? 1/4" (6.35 mm) with 3/8" ?- 32-NEF-2A bushing. Requires only one square inch of panel space. - 400 Series: 1" (25.40 mm) - 10 Turn Calibration. This world class turns-counting dial is designed for multi-turn potentiometers up to ten turns or other rotary devices. The knob/scale attaches directly to the shaft, and the body of the dial is mounted rigidly to the panel, therefore, accurate readings with a ratio of 1,000 to 1 for 10 turns are provided with no backlash or reading error. Available with or without locking mechanism. - 500 Series: 1" (25.40 mm) - One Turn Calibrated Scale. - 600 Series: 1" (25.40 mm) - Uncalibrated Dial. - 3400 Series: 7/8" (22.23 mm) - 20 Turn Calibration. Calibrated dial designed for multi-turn potentiometers up to 20 turns or other rotary devices. The turns counting digit appears in the window as the dial is rotated. Mounting bracket plate is installed between panel and panel nut, with the dial mounting directly to the potentiometer shaft.