This bracket screws onto the back of the High-Bright unit using the CineRT’s existing 4 screws.
This version also has an hexagonal slot which will accept a 1/4”UNC nut (full or half height) to allow you to attach a spider holster spud etc.
Use a 1/4”UNC screw to fix the bracket onto the HU-3’s mounting block.
Available in 7 colours
In the UK, I have found Westfield Fasteners a good reliable source for imperial nuts and bolts.