The D4 by ISC is a double stop device. It is designed to hold a static load of 4kN but to slip between 4-6kN so as to be able to be used as a fall-arrest/belay device. The D4 has a 22kN Minimum breaking strength, and is designed for loads up to 240kg.
The handle rotates all the way around (360 degrees).
Auto-lock function which is activated whenever the operator lets go of the handle.
It’s made of thicker aluminum than the Petzl I’D, so it is more durable.
Panic brake that is designed to only lock out when in free fall.
The anti-panic is somewhere between an Petzl I’D and a Rig in terms of sensitivity.
