Software

Unlike previous Finalmouse releases, which shipped with no software or other means of adjusting settings, the UltralightX does allow configuration, albeit browser-based. XPanel is hosted by Finalmouse and connects through the WebHID API, which as of now is only supported by Chrome, Edge, and Opera. Alternatively, through the web-app, a downloadable executable is also available, which does not require installing, but does occupy roughly 10 MB within AppData. Since XPanel exclusively connects to the wireless dongle, accessing XPanel in wired mode is not possible. All options are distributed across several tabs. The first tab allows for CPI adjustment between five pre-defined steps (400, 800, 1600, 3200, and 6400 CPI). The second tab has polling rate configuration: 500 or 1000 Hz in wired mode, and 500, 1000, 2000, or 4000 Hz in wireless mode. The third tab allows one setting lift-off distance to either 1 or 2 mm, whereas the fourth tab allows turning MotionSync on or off. MotionSync synchronizes SPI reads with USB polling events at the cost of up to an entire interval of added motion delay. On the fifth tab, one can set the dongle LED to either show battery charge or a solid light.

All setting changes are saved to the on-board memory, and any changes apply to wired mode as well, provided they are valid. On my system, the stand-alone executable had a RAM footprint of around 100 MB on average when running in the foreground, which doesn't change when minimized, be it to the taskbar or system tray. Upon exiting the application, all processes are terminated, as they should be.

Battery Life

Finalmouse states a maximum battery life of up to two months, which is largely non-descriptive without specifying the number of hours of usage per day or which polling rate is used. XPanel features a percentage-based battery life indicator with single-digit precision, which appears to be largely accurate and reliable. For every two hours of use at 4000 Hz, the indicator went down by 10%. Assuming linear consumption, roughly 20 hours of battery life thus can be expected.

Using the included USB Type-A to Type-C charging cable, I measured the charging speed during the constant current stage, which sits at around 0.131 A. The battery has a capacity of 250 mAh (3.87 V) and utilizes a 3-pin JST connector.