My Review of Logitech M570 Wireless Trackball - Can It Replace your Mouse?
Best Ergonomic Mouse? Logitech M570 Review - YouTube
Logitech - Logitech M 570 Trackball sans fil noir - Clavier - Rue du Commerce
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