Is that a 3AG fuse? I think this is the Littelfuse cap you need: 03453LS1HX020
Mouser sells them new, for under $4 Somewhere, I have a bunch of new PCB
mount fuseholders that take these.caps.

<
https://www.mouser.com/ProductDetail/Littelfuse/03453LS1HX020?qs=%2Fha2pyFaduibjiksbXA7YXS8whWaBMPfBXGEz8kYOYlXAWBaqr2TVg%3D%3D

HP used these, as well. It is series 345, <
https://www.mouser.com/datasheet/2/240/Littelfuse_Fuse_Holder_345_Panel_Mount_Datasheet.p-1317217.pdf

On Tue, Oct 6, 2020 at 1:35 PM Martin Hodge <mhodge@innocent.com> wrote:

Does anyone stateside have a spare Tek fuse holder cap/insert
(200-2264-00) they'd be willing to sell me? The only ones I can find are on
eBay out of Greece and will take a-month-and-forever to get here. I have
the option of replacing the entire fuse holder with one a have, but I'd
rather avoid surgery.