The C.E. Smith Roller-Bracket Assembly is a strong, hot-dipped galvanized bracket holding a non-marking, shock-absorbing roller to give you proper keel support. 5L x 17/32W slot for vertical adjustment. Pre-assembled. Lengths: 5, 8, 12. Cancer and Reproductive Harm- www.P65Warnings.ca.gov. Type: Tongue Jack Accessories.