Compatible Model: CO2 Quick Adapter replacement for Crystal 3.0, Duo, Terra, Art, E-Duo soda makers; compatible with CO2 refill adapter accessories and CO2 cylinder with TR21-4 male thread. Easy to Install: CO2 Quick Adapter features a split design for convenient installation without removing the machine base. Includes 3 replaceable rubber rings to replace aging, dirty, or damaged ones. Note: Slight color variations due to lighting or display differences may occur; this does not affect functionality. Color: Red Material: Aluminum Package Contents: 1 x CO2 Quick Adapter 3 x Replaceable Rubber Rings Only the items listed above are included; other products are not included. Note: Lighting and screen settings may cause slight color differences between the image and actual item. Measurement error allowance is +/- 1-3 cm.