A replacement retainer for these 4'' flat b/w CRTs from aliexpress with a mount for the video and power connectors

Better than the original piece because it is not under as much stress due to not conforming that well to the shape of the tube.

The connector I used is cobbled together from a double decker RCA video connector and a 12v barrel plug pasted to the lower part with hot glue, but you can also use the recreation I made of the original plastic retainer to add your own mount to it.