Summary

Mount for a 5 wire grounding bar with mounting screws on the bottom

It is made to fit this: https://www.amazon.com/gp/product/B07DJ65H8S/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

Bar Specifications:
Size: 4.5 x 1.8 x 0.7 cm / 1.8 x 0.7 x 0.3 in
Screw Size: M5