Heavy-duty Fusetron , dual element, time delay FRN-R dual element cartridge fuse for motor protection. Helps protect motors from burnout caused by overloads or single phasing. Time delay feature allows the initial startup surge for typicalmotors to pass, but opens prior to burnout when longer dangerous overloads are present. UL listed Class R 200,000 AIR (amp interrupting rating). 1/10A to 60A have ferrule ends, 70A to 200A have knife-blade ends. 250V.