Panasonic SA-HT750 Speaker Stand Coupling

My Panasonic SA-HT750 surround sound system is great. The only problem with it are the speaker stands, specifically the plastic coupling piece. As you can see in the photo, they break. There is not too much to them, just some thin, injection molded plastic.

One was completely destroyed, the other had just started cracking. I took the 'good' one as a reference and tried to model something that would do the same thing but also look okay. My coupling doesn't have a feature that goes on the insid