Breathing Circuits Standard connector (15mm, 22mm) Colored EVA CE approved 1.6m or 1.8m Breathing Circuits Standard connector (15mm, 22mm) Colored EVA CE approved 1.6m or 1.8m1. Different length of circuits are available2. Anesthesia breathing circuit is used during surgery, it is the interface or link between the patient and anesthesia machine. The circuit is a pathway that conveys oxygen and ...