RocknRoller Multi-Cart Extension Rack instantly attaches/detaches to either end of Multi-Cart increasing cubic cargo capacity by approximately 20%. Great for carrying odd shaped, hard-to-stack gear and saving that one extra trip to the car. Sturdy powder-coated steel tube frame. Platform dimensions 13.5" x 10" x 1.5". Weight: 4.4 lbs. Fits R6, R8, R10, R12