Which SR Blue or black Fuse


Which SR Blue fuse for ARC REF 5SE? It says 5A slo/blo 250V on the fuse but no size MM?any help? Anyone had any experience with either fuse and what was the result.
dskinner5
@glupson I recently had an AC fuse in my IEC connector blow when switching from triode to UL mode. Turn on and switching surges popping fuses is not as uncommon as you may think.  In fact you can search the forum and find others here posting about it over the years.
Post removed 
I had a Hifi tuning fuse  blow up for no reason  A few years back. 
 Why bother taking the risk, even if it’s minuscule, for absolutely zero gain? 
Sounds like operator error. No offense. There’s a reason for everything.