Here is a simple 3D model for standing a shampoo, conditioner, detergent, or liquid soap bottle upside down. The diameter of the hole for the bottle cap is 31.5 mm. If you need a stand for a different diameter, let me know, and I’ll generate it, or you can download the Fusion 360 or STEP file and modify it yourself. I printed mine in white PETG with 15% infill.
