Hands-on: Logitech MX Ergo wireless trackball mouse | ZDNET
Amazon.com: Logitech M570 Wireless Trackball Mouse – Ergonomic Design with Sculpted Right-Hand Shape, Compatible with Apple Mac / Microsoft, USB Unifying Receiver, Dark Gray (Discontinued by Manufacturer) : Electronics
Hands-on with the new $50 Logitech Ergo M575 Wireless Trackball - CNET