The D4 has a 240kg (500lb) Working Load Limit which means it is suitable for two-man rescue on ropes of 10.5mm-11.5mm (7/16"). It features a unique and innovative progressive cam action, which offers precise control at slow or fast speeds. The progressive cam works by way of one cam operating inside another cam.
The D4 is a double-stop device with an auto-lock function which is activated whenever the operator lets go of the handle.
The D4 meets the requirements of EN12841, NFPA 1983 and ANSI Z359. For information on EN341 please download the PDF below. The D4 has an operation temperature range of 50oC to -30oC.