I have a green planet cheapie pipe that has a air passage drilled straight down in the bowl, then the air passage from the shank meets with it. No matter how I tried to pack the bowl, tobacco still eventually was drawn into it, and clogged it up. So I grabbed a 5 pack of them from my local B&M, and tried them in the pipe. It works great, up until the point that the excess moisture from the tobacco starts to fill the air passage, which is when I just give up smoking it. (Usually about the bottom of the bowl anyway) I also use them in my MM cobs, as I cant stand the filter and don't like sucking in hot dottle or unburnt tobacco leaf.