This is a form fitting trackball tray and support for the

Logitech M570 Wireless Trackball Mouse

and mounts to my SimLab PSE USB Wheel mount back.

It uses M3 bolts and M3 threaded inserts as well as "VELCRO Brand - Sticky Back Hook and Loop Fasteners | Perfect for Home or Office | 3/4in Coins"

To mount this I used an ice pick to poke holes in the back of my PSE USB Mount back and then melted those holes open to insert more M3 threaded inserts as shown in one of the pictures.