This is an underdesk/wall mount set to mount the Amazon Basics surge protector strip. There is an existing one on Thingiverse but I couldn't get it to fit. These mounts also allow you to use the last outlet.

This fits: https://www.amazon.com/AmazonBasics-6-Outlet-Surge-Protector-Power/dp/B00TP1C51M

Print one of each end.