White resin ball. I have confirmed operation with my PMW3610-equipped keyboard, but individual operation is not guaranteed as the firmware and sensor angle adjustments vary depending on the keyboard. If the sensor recognition is poor, please investigate and make adjustments yourself. It has been lightly cleaned and coated, but it will deteriorate over time, so please use it while performing regular maintenance. This is a set of two for that purpose. It is not a completely glossy finish like commercially available trackballs. It is difficult to reproduce the color of the ball in the photos, so please use them as a reference. Compared to the trackball case I have, it appears slightly bluish. It will be shipped via post-in format.