The Kensington Pro Fit Ergo TB550 is a a dual wireless thumb-operated trackball, on July 31, 2023. This ergonomic wireless trackball offers Bluetooth LE or 2.4GHz wireless connectivity and features a 45° inclined body with a "handshake angle" design for comfortable grip and operation.

Equipped with a maximum 1,600 dpi optical sensor, the trackball allows users to switch between four resolution levels (400/800/1,200/1,600 dpi). The patented ball eject button facilitates easy maintenance around the sensor area.

The device boasts a total of 8 buttons, including forward and back buttons, with support for function assignment using the "KensingtonWorks" software for 7 buttons.With external dimensions measuring 93.5 mm wide, 138 mm deep, and 50 mm high, and weighing 143 g, it comes with a built-in lithium-ion battery that provides approximately 4 months of usage on a single charge.