This light collar is heavy duty and is designed for the Pro PDR Solutions Chubby lights. Please Note: Some Pro PRD Solutions’ Light Stands have a 3/4″ in boom. If you are unsure of which Collar to order, measure the diameter of your light stand’s boom. Currently, no model is available for lights with Ultra Ball on the back of the light. Your light must have Pro PDR Solutions’ attachment on the back of your light.