We now have the Irwin Seating Bleacher Drive Wheel on our website. The Irwin Seating Bleacher Drive Wheel measures 6″ Diameter x 9-1/2″ wide x 3/4″ axle with key way. The axle is 15-1/8″ long. One 20 tooth sprocket included for a 50 link chain. The construction of the wheel is steel with a neoprene roller surface. The Bleacher Drive Wheel was also used on Folding Bleachers. They ship within about 2 weeks. There are other variations out there, and we can get them also. Call or email our Bleacher Experts!