A non-sterile device intended to, when integrated within the common line of a breathing circuit (open or partial rebreathing), absorb and desorb (i.e., recycle) exhaled volatile anaesthetic agents; it may also be used to facilitate monitoring (e.g., gas concentration and pressure, breathing activity) via connection to breathing system components. It is typically a housing containing an anaesthetic gas absorption/desorption filter, and may include sensors. This is a reusable device.