Kensington Expert Mouse White (a now-discontinued Japan-exclusive white color model) Used until the end of the year. - Used only in a non-smoking environment. - However, the ABS resin has yellowed, so it's now beige instead of white. - The ball is smooth with no discoloration or scratches (confirmed by swapping it with a SlimBlade Pro). - USB connection only. - Palm rest is unused. - All switches and the wheel function normally, but I haven't checked all the functions configurable in KensingtonWorks, the Kensington trackball utility. - Usable with the latest version of KensingtonWorks v3.1.18. - The Kensington nameplate appears to be cracked. Experience the 55mm large ball! The 55mm ball alone costs around ¥4000 on Amazon, so I'm offering this for less, how about it as a spare ball too??