The Speed Rail Mounting Suction Cup Kit from Tilta is a set of four high-capacity cups, each designed with sturdy aluminum, stainless steel, and rubber to sustain payloads up to 110 lb. These work perfectly with the Tilta Speed Rail Car Mounting Kit but are compatible with any 50mm speed rail. When used with other Suction Cup units, a very stable foundation for mounting shock-absorbing arms or other gear is established.