Kensington PocketMouse Pro, Optical, USB Type-A, Silver Kensington PocketMouse Pro. Movement detection technology: Optical, Device interface: USB Type-A, Buttons quantity: 2. Product color: Silver Mechanical rolling balls, besides requiring frequent cleaning and de-crudding even in tidy offices, dont always work well on airline tray tables or other places a full-sized desk and mouse pad arent available. And packing a mouse in your briefcase is...