These can certainly save your stems and your teeth. I am glad they are back after being on backorder for a while. A few weeks ago, I ran across an old pipe cleaner bag with an order form for these from many years when they were 4 for a dollar. I may send it out just to see if the company will honor it. I've used them for a long time. I'm so used to them, a pipe without one feels strange.
All I can say is "BUY SOME NOW!!!" I bought a pack of 2 (I have 4 pipes) with the intension of swapping the bits from pipe to pipe when needed... Well lets just say I ordered 2 more packs... You see what I just did there? I can now very tactfully point out to my lady "I have 2 extra pipe bits... I wonder what I'm gunna do about it, I know I'll just have to buy 2 more pipes!" Maybe she'll go for it? These are the best no fears of chewing up a new pipe!
These pipe bits are a perfect fit for my Medico standard pipe. I've been using the same bit for three months and it still has no signs of wear. It never comes off by itself, it hugs the tip of the pipe perfectly. It's very comfortable, and never bothers my lips or teeth, I barely notice it's on.