The Ashford Basic Jumbo Flyer Unit fits Ashford Traditional and Traveller Single Drive Wheels. Its great for spinning bulky yarns, plying thick yarns or spinning large quantities of yarns. It Includes the Jumbo single drive 4 speed flyer, jumbo single drive bobbin, front jumbo flyer bearing, bearing reducer bushing, orifice reducer bushing, drive band, brake band, 2 springs, threading hook and instructions. This unit requires replacing the original front bearing with the jumbo front bearing included in the kit. Jumbo bearing inside diameter is 3/4" (19mm). Bearing reducer bushing allows use of original standard flyer. Orifice reducer bushing allows for finer spinning. Orifice bushing 3/8" (10mm) ID. The Jumbo flyer has 4 Ratios: 4.5, 7.5, 9.5, and 13.5 to 1. Flyer and bobbin are unvarnished.