The Cooper Bussmann FRN series 15 amp Brass Time Delay Fuse Cartridges are dual-element, class RK5, current-limiting time delay fuse cartridges with a 10-second minimum at 500 percent design. These fuse cartridges are typically used in power panel boards, motor control centers, combination starters and machinery disconnects. These fuses have fiberglass tubes and are UL and CSA listed for safety. For use in power panel boards, motor control centers, combination starters and machinery disconnectsDual-element, class RK5, current-limiting time delay fuse cartridges250 voltFiberglass tubes2 per card15 amp