MB-7 is designed for any of the PTR-10 series and use the WM-11 professional Wall Mount with up-side-down circumstance, then you need the MB-7 Long Arm for PTR accessory to install.
Long Arm Accessory for All PTR Series (Upside-Down Installation)
Designed for use with all Datavideo PTR series robotic pan tilt heads
Enables secure and stable inverted (upside-down) mounting
Provides extended clearance for optimal positioning and cable routing
Ideal for ceiling or overhead installations
Durable metal construction for long-lasting reliability