I replaced one of my wheels and the new one was Presta valve, so wanted to switch the other wheel from Schrader to Presta. Another company makes a screw on the valve type, but I knew if I got that style I would loose it after the first flat.
This product goes inside the rim hole, so unmount your tire and tube then push the Stem Saver into the hole drilled in your rim for a Schrader valve stem, and then remount your tube and tire. I already had cloth rim tape, so it covered nicely, so I won't loose it. Yea these work great!
I think this is well priced and fits the rims well.
Odd as it may sound, I bought these because the cost of these adapters and two presta tubes was cheaper than buying two schrader valve tubes.
I think it's a good idea to have schrader drilled rims regardless of which tubes you're running so that you can fit any replacement tube when you're stuck somewhere. These things let you do that.