XR Rails are the backbone of the solar array. Their unique curved profile increases structural strength and spanning capability, allowing for fewer roof penetrations and more cost-effective system designs. XR Rails can be easily extended with IronRidge's patented internal splice bars. The internal splice bars do not interfere with clamping or with mounting, and offer a near seamless appearance. XR Rail Splices are made with extruded 6000 series aluminum. Self-drilling screws are included.