4 x 4 Part D Aluminum Spool CouplerThe 4 x 4 Part D Aluminum Cam and Groove Spool Coupler is a female camlock coupling with a spool extension, designed to connect male camlock adapters securely. This coupler is used in fluid and material transfer systems, providing a reliable, leak proof connection between hoses, pipes, and equipment. The spool section allows for extended reach or spacing between fittings, making it useful in industrial, agricultural, and chemical applications.