INLINE 400 Amp Class T Fuse mounted on fuse block with clear plastic cover.
Fuse blocks provides 3/8″ threaded posts for connections to cabling with ring terminals. A fuse and holder is basic protection against electrical fires from over-current in wiring.
Fuses and holders by themselves are not accepted by National Fire Code unless mounted in an approved metal box.
Replacement fuses, O-T400, available from Backwoods if you do not find them locally.