Ignition protection means it won't let a spark out that can start an liquid or gaseous flamables on fire. There is a pocket that contains the sparks if any and keeps out other things
Earlier I stated there was a universal class T holder - drum roll, I was wrong - I know I know you are either thinking "WHAT!! never" or you are thinking "What, again??" Here are both sizes of the "ignition protected version. There is indeed a pocket that is totally isolated from outside air...
diysolarforum.com
Pictures of the fuse holders.
And the difference in sizes. I was wrong. The current connected website states that it fits 'any' fuse up to 160amps. I missed the tail end of that and interpreted it to mean it was universal.