7 speed Freewheel sprocket 13-34 HG-50 Shimano Hyper glide compatible. Our custom hubs use "thread on" freewheels, not cassettes. See the difference in "Freewheels and Cassettes". Most bikes that cost over $400.00 will use a "cassette". If your wheel has a cassette it's better and cheaper to buy a New Double wall Alum rim and order the 7 speed freewheel. This way you can keep your old wheel or sell it to cover the cost of the new wheel. Our CNC machined Four bearing hub made in the USA is probably much better then the hub you know have.