fuse for audio research D-400 mk2

Has anyone know the kind and rating of fuse of power amp audio research D-400mk2?

I would like to upgade the fuse at rear panel of amp but I can not see anything on old fuse.

Thank you,
The fuse rating should be on the silver end caps of the fuse.
Yes I tried to read from that but I could not see anything. It's very light.

Thank you,
You can call ARC speak to Chris in service....He will tell you what the fuse is supposed to be.