The Logitech M570 810-001807 Trackman Wireless Trackball Mouse is out of production so good, functioning units are becoming more and more scarce for longtime users who rely on this ergonomic classic.
Here's a great unit that

• Works perfectly
• Includes the Logitech wireless USB dongle inside the battery compartment for convenient storage
• Includes the original package and user manual
• Has been thoroughly tested to function like new
• Requires you to supply your own standard AA battery

You'll notice in the detailed photos that the logo is almost completely faded, that the plastic surface has some discoloration, etc. So if you're a stickler for a perfect, beautiful unit, you're better off looking for a new, sealed unit and paying the premium for it. But if you want one for a good price that works perfectly and includes everything, then this listing might be for you.