Here is my youtube vid. of the mini torch. This is with the my second gen. that only produce like 1 lp 6min. When you watch it I open up the needle valve with the pliers when it is still lit. You here a pop right there from the flash back. I then try to light it while its still open showing the cig filter works. You can here the pops.

If you look really closely you can see the flash go to the filter. The flame is near invisible at the tip.
http://www.youtube.com/watch?v=uN4Mer2Zv1U