is positioned with its end cap fitting into the conductive contact ring 32 of the fusing mounting body or cover 31 so as to be held thereby each of the second group of elements 50 is in accordance with an aspect of my invention similarly shaped with the first group of elements 30 and may thus be similarly inserted into mounting elements 11 in the fuse and indicator block 10 as seen in fig2 each of the elements 50 defines a visual indicator and comprises a hollow sleeve 51 a first electrical contact 52 including an electrically conductive key 53 adapted to be inserted in channel 16 such that electrical contact is established with terminal 14 and the visual indicator is firmly held in the mounting element 11 the key 53 cooperates with channel 16 and a stop 54 such that sleeve 51 can only be inserted into mounting element 11 a limited distance a light emitting diode 55 is inserted in the end of the central aperture 56 in the sleeve 51 such that an electrical terminal 57 of light emitting diode 55 is electrically connected to terminal 52 and key 53 and a second electrically conductive terminal 58 of light emitting diode 55 is connected to a first terminal of a resistor 59 a second terminal of resistor 59 is connected to a second electrically conductive terminal cap 60 which is adapted to establish an electrical contact with terminal 12 of the base of mounting element 11 it may be desirable in certain applications to provide some means of insuring.