Topek frame pumps.
This is a pretty pump, some other people think some other pumps are better looking, but I think this pump looks great and works better than any other pump I've used.
The best part of the pump is that the center section is threaded on both sides so it's great to take apart for paint or polish, and it looks good as it.
If you are using them on pump pegs on the seat stay you will probably need the S. You can get away with a medium on frames above 57cm.
If you jam then in anywhere other than the seatstay other sizes can come into play.
I recommend buying the stock one if you are going to have the bike painted so you can pull the pump apart and have it painted/powder coated to match. Also if you have a more modern looking bike.
The polished one is the thing for a bike with lots of vintage, polished and moded out custom bike that's already been painted or chromed!
The small actually measures between 38 and 42 cm depending on spring compression.
The medium measures out at between 42 and 46 cm. So measure those pump pegs to drop outs before ordering a pump!