From the ManufacturerMersen TR20R 250V 20A 2X9/16 Rk5 Time Delay Fu, UL Power Fuse, Class Rk5, Time Delay Characteristics, 250 Vac/160 Vdc, 20 Ampere, Interrupting Rating 200 Kiloampere (Ac), 20 Kiloampere (Dc), Ferrule Terminal, Diameter 9/16 Inch, Length 2 Inch, Approval Ul 198L, Ul 248-12, Csa C22.2, Tri-Onic[R] Brand, Tr Model