The Hobie H-Rail Bolt On Kit 21" is a set of components designed for the Hobie kayak. The kit includes an H-Rail and hardware, allowing it to be mounted onto the kayak. The H-Rail is 21 inches in length and provides a versatile platform for mounting accessories, such as rod holders, lights, and cameras. The kit is easy to install and provides a sturdy and secure base for mounting accessories. The Hobie H-Rail Bolt On Kit 21" is a useful accessory for kayaking and fishing enthusiasts who want to expand the functionality of their kayak.