Multiboard accessory installation backing tool

I absolutely love the Multiboard system and the community around it. One frustration I'm having is that the boards are flexible, and the insertion of attachments can be difficult because of this. This slides into one of the octagonal holes, and slides behind the board opening you're installing into. I made a pair of them, since most accessories use two attachments. Prints well in PETG and ABS, I haven't tried others.