price is per 1u server set. each item includes one left and one right outer rail. picuted is a bundle of rails.The used Supermicro 1U 25.6" to 33.05" Threaded Hole Server Outer Rail kit is a high-quality rack accessory designed for server mounting. It is compatible with specific Supermicro chassis models, including CSE-815, CSE-818, CSE-113, and CSE 512F. The outer rail extendable length ranges from 25.6" to 33.05", providing versatility in accommodating different server sizes. this kit ensures you can remove the server below it without it falling.