This is what I am talking about >> https://www.wirebarn.com/30-Amp-Automotive-Relay-with-6-Socket-Pigtail-Plastic-Tab_p_193.html
A relay actually does not have a fuse...Usually a fuse is either wired into a relay box to use for the acc, an inline fuse is used, or the accessory has it's own fuse...all the relay is an electronic A/B switch (in a single pole, double throw relay)...or a DPDT (double pole, double throw) is like two A/B switches in one (in very layman's terms)...
Pole - how many inputs
Throw - how many outputs
Again in layman's terms because a SPDT can be used in reverse (like two inputs and one output)