The Cokin 54mm Hasselblad Adapter Ring is a new old stock product designed to allow a Hasselblad lens to attach to a Cokin filter holder. This adapter ring is made by the reputable brand Cokin and is specifically compatible with "A" sized filter rings. It provides a seamless way to incorporate a Hasselblad lens into a Cokin filter holder system, offering versatility and convenience for photographers using both brands in their photography equipment. Please email with questions.