Originally designed for my custom subwoofer enclosure. Wanted to hook up both voice coils to change impedance without removing sub from box. Also to wire each voice coil to separate amplifiers.  Terminals are suitable for heavy gauge wire 10, 8, or 4. Uses 9/16" bolts, nuts, and washers for hardware. To be used with 3 inch hole cutout to install. I installed on ¾" birch plywood. There are different versions one with the nuts recessed to keep from having to tighten bolt from opposite side of terminal. Other versions that are not recessed are intended to be used with split washers. 

Also added different models for a single positive and negative. One is flat to print without supports. Still uses 9/16" hardware and a 3" cutout.

Recently had a request for terminal cup with dual post with the nuts recessed.

Print with Supports back of terminal on print bed.