Park Tool STL-3K Backrest For STL-1. 2 Does your back get sore when you're wrenching in your STL-1. 2 Stool? Some jobs like wheel truing, fork overhauls, and brake bleeds can be tedius and time consuming, causing your back to tighten up after long periods of time sitting at the work bench. Thankfully, Park Tool has you covered with their STL-3K Backrest. It attaches easily to your stool, giving you comfortable back support while you wrench away. The padded backing is plush and easy to clean, making it a practical addition to your shop. Features Compatible Stool: STL-1. 2 (STL-1 is not compatible) Manufacturer's Part No: STL-3K UPC: 763477007155 | Park Tool | Stl-3K Backrest For Stl-1. 2 | Black | For Shop Stool Stl-1. 2