. . that sort of fuse is usually in an in-line holder, in other words sort of plastic lump on a wire. The lump is usually in two halves that lock together with a twist and if they came untwisted the fuse would fall out. They are most common for "add-on" equipment like radios but may be used for standard equipment too.

As for the 250V rating, what matters to a fuse is amps and they have very little resistance so voltage has a very small effect above fractional volts. Most glass fuses of that type are rated 250V regardless of the voltage of the system they're used in.