Wear your Garmin Edge 25 on your wrist with this mount. The mount uses Garmin's 90-degree twist. It is designed to be used with a band for the Garmin Fenix 3 and 5X.
The Edge 25, of course, is meant for tracking bicycle rides. You can wear it on your wrist for this use. However, you can also wear it while walking or jogging. While this won't count your steps, it will provide you with total distance, average walking speed, etc. It also provides you with the time of day!
This build uses a previous posting on Thingiverse for the basic mount design (Thingiverse model: 1329407, which is described as "Support Garmin Edge 1000") but adds the structure to mount available wrist bands.
In addition to printing the part, you'll need to acquire a wrist band for the Fenix 3/5X size (26mm width), as well as the attachment pins--all of which are readily available for a modest cost on eBay and Amazon.
Print the mount in high definition (10mm layer height or less) and 50 percent infill or more. Clear the holes with a hand-held drill-bit of the appropriate size to make it easy to insert the pins.