This is a tool tray for three 3/8 extension bars: 3-in, 6-in, and 10-in.
It should fit pretty much any of those standard 3/8 extension bars.
This object was made in Tinkercad.
Edit it online https://www.tinkercad.com/things/cLX8xq07V7E
cLX8xq07V7E.stl | 73.4KB |