White Elephant 9mm don't have to go in any specific way, so I assume the 6mm would be good either way as well.are they supposed to go in a certain direction, like the Vauen 9mm filters are supposed to have the blue on the stem side?
Also, I just got some Dr Perl 9mm, and they've got rid of the blue cap. Now you can put them in either way, just like most other brands. However, the ones I got are substantially smaller/narrower than any other brand I've had. The only pipe they really fit in is an Irish Seconds pipe I have