Unit is a Aerotech 16" gimbal mount.

Product description:
-Clear Aperture: 15.50"
-Rotational Freedom: 360Degrees AZ / 360 Degrees EL
-Adjustment Know: +/- 3 Degrees AZ/EL
-Component Diameter (max): 16"
-Component Thickness (max): 2.5"
-Component Weight (max:) 160 lb
-Material: Aluminum
-Finish: Black Epoxy Paint
-Weight: 64 lb

The add on sizer shown in this photo is included in the cost of the mount. We have two lens available for this mount. Please see related items below.