Miniature blade fuses are one of the most common type of fuse for automotive and marine applications, but can be used in other low voltage electrical applications that require circuit protection. Housed in transparent plastic that is universally colour coded to indicate current rating. Commonly mounted in a fuse block, fuse holder or panel.
The LED indicator in this fuse lights up when the fuse is functioning properly and the circuit it is protecting is active.
We suppose that technically, this means if the LED switches off, it becomes refuse!