No instructions but once I figured out how to remove the belt from the buckle I just cut it to the perfect size and snap it back together. I don't know anything about durability yet, but the straps look good and appealing. To update. Downgraded my rating from 5 to 2 stars. Bought these belts on July 16, 2021. Tonight, November 24th, the buckle broke where it transitioned from brown to black. There is nothing I can do to restore it. It should last more than four months. I wear the belt almost every day. Since there are two straps in the kit I'll put the second one on and see how long it lasts.