I couldn't find this idea in the forum, so here goes.
A filter; usually the mark of a cheap pipe... but not always. When I was younger I smoked almost nothing but English, but as I got older I've had to tone it down a little. I guess I would be called a heavy pipe smoker; uaually about 10 bowls a day. I need something that doesn't rip the hide off my tongue after a few smokes. During the day I smoke Raleigh. That's right good old cheap, drug store Raleigh. I enjoy the taste and it doesn't scorch my tongue. The last couple of bowls in the evening are usually English of some type.
Different pipes smoke different tobaccos differently. I found that for Raleigh I get a good smoke from the Savinelli filter pipes and I do use the little balsa filters. I really think they are a rather clever and simple idea. All they do is absorbe moisture and tars but don't change the taste. I think they are more of a "passive absorber" than a filter. I like em.
What I don't like about them is the price. Even at wholsale I think they're overly expenive. I usually get 2 or maybe 3 smokes before I replace it and over a years time it can run into money. So, being a cheap s.o.b., I decided there had to be a better and cheaper way. I don't buy them any more. What I did is I bought a batch of balsa rods off ebay. 50 rods, 3 ft. long, 1/8 by 3/16 inchs, rectanular. Then I snap off little pieces in the right length to make my own. Cost about $15. and makes about 1000 filters. Trust me, the smoke doesn't care if they're triangular or rectangular. It works great and I figure I cut my cost big time.