If you're looking at this, then you probably already know what it is and what it does.
Amazing "tweak" that offers real sonic improvement. If you'd like more info as to the "how" & why it works, then please refer to the link to the Synergistic Research website under 'More Info' above.
Note this is the "Large" 1.25-inch (6.3 x32mm) size fuse.
My personal recommendation is in a pre-amp or phono preamp, however those who have tried these SR Orange fuses report improvements in various audio components, and there are plenty of user reviews available online if you need to do some further research (no pun intended).
Asking price includes PayPal and U.S. shipping. Will be protectively packed and shipped in an outer box (i.e., "double-boxed") in addition to its complete foam insert encasement in the original SR box.