This wireless computer from UK retail chain Halfords has a couple of valuable features for the money: you get a backlight and you can input two different wheel sizes.
A separate second sensor, which you can order in-store, costs £7.99. The two-line dot matrix display can be difficult to read at certain angles but it’s clearly labelled with your speed above and the choice of several measurements below, including average and maximum speeds and the temperature.
The single button sits flush with the screen so it’s difficult to feel in gloved hands but it worked reliably throughout testing and you can set the display to scan if you prefer.
We experienced no interference to the signal and the speed sensor’s battery power tester is a useful touch. Switching between bar and stem mounting is a faff compared to some other units though, and so is changing the battery.