The Stepper base is the anchor of the Ultimate Hose Clamp. It attaches to the rear of the standard nema 23 motor mounts with optional standoffs and connects to arms.

Overall view of the UHC Stepper Base

The U-Shaped metal piece connects to the nema 23 motor. The screws go into the holes, and hold the Arm, by grabbing onto the imbedded square nuts. 

The spacers (dark grey as pictured, but black upon receipt) serve as spacers at your Nema 23 motor counts. 
You'll receive 4 spacers (2 pairs), they can be used as either or but not mix and matched. 

They're available for purchase and included within the maker files pack for our Ultimate Hose Clamp.