Scottish startup Una has launched a $249 GPS running watch designed to be user-repairable, modular and open source. Its approach offers owners more control over their device and could support a community of developers, but the design involves durability and hardware trade-offs.

The 46mm watch separates into six replaceable parts, and its software, case and circuit-board designs are available on GitHub. It has a 1.2-inch, 240-by-240-pixel display, 4GB of storage and a 280mAh battery; the reviewer got seven days’ use, while Una estimates seven to 10 days of battery life and up to 20 hours of GPS use. Its IPX5 rating limits protection to rain, sweat and light splashes, making it less suitable for demanding conditions.