The camera could be slid and adjusted along the middle groove, and accessories can be mounted via the 1/4" and 3/8" threaded holes. There are screws and rubber cushions for camera attachment and protection. It could be used to directly mount camera, cage and tripod etc.
On bottom, there are 15mm LWS rod clamps for matte box, lens support and follow focus. It enables use of standard accessories for the 15mm rod system.
The wingnuts are used to mount or release the rods conveniently.