This device is an at-home beverage machine made by SodaStream. The purpose of this device is to make carbonated beverages in the convenience of your own home with the use of syrups and the machine. This particular model was originally manufactured in approximately 2007.
examinerbill SodaStream does not sell any parts but the washer appears to be a standard gasket. I'd measure the inside diameter and the outside diamter plus the thickness. Armed with that you want to shop around at places like this and others