A fuse:
1: two end caps
2: short piece of fuse wire connecting the two end caps through a glass tube (that’s all she wrote).
To those "non technical" members that are interested, do not listen to fusers, listen to the technicians of this industry that design your audio products that you have.
AND YOU WON"T SEE THEM ON THREADS LIKE THIS AGREEING WITH THESE FUSERS ABOUT THE SONIC IMPROVMENT DETAILS, AND EVEN MORE ABSURD, AC MAINS FUSE PLACEMENT DIRECTION!!
Just do this before spending your hard earned dollars, and giving it to these very suspect website outlets .
Just clean and tighten your fuse holder and re-new your fuse (if old) with a good quality 50cent Bussman, Littlefuse or similar.
As with "many switch-on surges" they do deteriorate, bend, stretch and get crusty with electrolysis formations on their fusible wire elements before they give out, as these pics show of a fuse wire element ageing over time show. https://ibb.co/9NbTwqK
(even the $$$ boutique ones will age just as much also)
Cheers to those "non fusers" George