What Are All Those Buttons? Flight Apprentice Hytrol B 15537 580 26 RLR 3.75"RC #50 72 1 2"BR SET LEFT. Replacement 26 rlr 3. 75"rc #50 72 1 2"br set left for Hytrol conveyors. This genuine Hytrol roller B 15537 580 is designed for reliable performance in your conveyor and is covered by the Hytrol warranty. Ideal for spare parts, repair, and maintenance, this part helps keep your conveyor line running smoothly. Shop our trusted Hytrol parts for fast shipping and expert support to minimize your downtime. If this item has been superseded due to improvements or discontinuation, well notify you immediately and provide the updated replacement to get you back up and running fast. Need help with specifications or to ensure you have the right part? Contact us for details, expert support, or manuals we are a premier Hytrol Integration Partner chat, use the Contact Us form, or call now.