Cine RT Ultra Sonic Base Bottom Mount
This bracket screws onto the back of the Ultra Sonic Base unit using the existing 4 screws.
It has an hexagonal hole in the base which accepts a half-height 1/4”UNC nut to give you the option to mount the unit from the bottom.
Available in 7 colours
In the UK, I have found Westfield Fasteners a good reliable source for imperial nuts and bolts and the link above is to their site.