Simple, full functioned, easy to install, inexpensive and it works very well.
It displays cadence, speed and distance. Optionally, it can show time.
I put one on my Swift Folder and got a second one form my wife's Swift.
I had tried a much more expensive, Polar wireless bike computer. But it worked erratically on a Swift because it has 20", 406 mm, wheels and the wireless wheel rotation detector was much further from the computer, on the handle bars, than it would have been on a mountain bike or a road bike. The signal just wasn't strong enough.
The Topeak 140 is wired. That means no signal distance problem.