found at DigiDirect
The Elinchrom Speedring for Profoto is required for mounting Elinchrom Quick-Open Softboxes on any flash head utilizing a Profoto mount. Elinchrom modifiers do not include speedrings enabling you to combine them with any lighting system with out incurring extra costs This lightweight, metal speed ring is compatible with Elinchrom sizes and shapes and will enable direct mounting to many Profoto strobes, including but not limted to B1X, B10, D1, and D2.