The Fusetron FRN-R-1 fuse an FRN-R series, Current-limiting time-delay fuse, 1 A, Dual, Class RK5, Non-indicating, Ferrule end x ferrule end, 8 sec at 500%, 20 kAIC at 125 Vdc|200 kAIC at 250 Vac, Standard, 250 V, 125 Vdc