DT Swiss 12-Mm-Thru-X-157-Mm-Super-Boost QR x 135mm Bicycle Rear Hubs
About DT Swiss - Driven by the vision of becoming a worldwide known manufacturer of bicycle components, DT Swiss expanded its product range over the years. Today DT Swiss has established itself as a leading manufacturer of spokes, nipples, hubs, rims, complete wheels as well as suspension systems.
This is hub spacing and is the width of the hub. It must match your frame specifications.
QR x 135mm, often called QR or Quick-Release mountain / hybrid standard.