The Ullman Devices Magnetic Rails, Nos. UMR13 and UMR17, use strong N35 magnets to mount to benches, boxes, and vehicles to securely hold sockets and metal tools. The rails also have mounting holes to adhere to walls and other non-magnetic surfaces. The UMR13 measures 13-1/4" in length while the UMR17 measures 17-1/4" in length.