The Elinchrom Adapter Ring Inner diameter is 5.31in/135mm, replaces the same size of different brands of adapte rings, such as Bowens, Profoto, Balcar, Hensel, Einstein, Broncolor, Comet, etc. Usually used to replace the adapter ring on some photography lighting accessories, such as softboxes, spotlights, etc, to make it compatible with Elinchroms Flashes, Monolights, and LED lights.
Note: The 135mm Elinchrom Adapter Ring can be compatible with Aputure Light Dome light Softbox, Triopo softbox and NiceFoto softbox.