This converter makes the normal PET bottle could be used with Soda Stream sparkling water maker. The konverter20 is for a glass bottle witch has a very small 20mm hole Print this watertight PLA or PETG no support needed on some printers maybe some sealing is needed. I suggest slow printing and maximum 0,2mm layer height. !!!!I used a plain rubber for inner thread. !!!! Not watertight without sealing!!!!! Work in progress