This is a modular sunglasses holder. It uses a 1in piece of PVC pipe for internal structure for the add on modular pieces. Just print as many sections as you need and cut a piece of PVC pipe to the length you need. The original base in the picture did not have a holder. I added it in the version that is uploaded.
For one pair of sunglasses you only need the base. For additional pairs of sunglasses cut a piece of 1in PVC pipe to size. The modular sections will fit perfectly. Make sure you're using schedule 40 PVC (it's the white kind).