Summary

This is a very simple part concept that's been kicking around on my hard-drive for a while.

It is a modified version of part 22961, Axle and Pin Connector Hub with 1 Axle.

The original part used in the old Matoran builds, Part 32579 "Bionicle Head Connector Block", has a very important feature that I don't think is discussed too often. On the back of it are two vertical bars that allow you to store the Matoran's Throwing disk without it needing to be in their hands. It's pretty nifty, all things considered. Unfortunately, that part is butt-ugly and doesn't allow for any sort of colored eye-stalks to be used, so most eschew it in favor of a Mata head. This part allows you to use the nice-looking Mata head while also allowing them to hold their disks on their backs!

The clip may be a bit tight, but I've had some issues with poor grippage in the past, so it may just depend on how it's printed.