Abstract: A bag for the recovery of used freon from an operational system comprising a bag formed of a strong lightweight flexible material having side walls which are cylindrical when expanded and having a closed outboard end and an open inboard end; sensor means within the container to indicate the percent of fullness of the container, the sensor means including a vertically extending support post coupled to the interior surface of the side walls and with an aperture extending centrally therethrough, the axis of the aperture being coextensive with the axis of the bag when expanded, a rotatable shaft secured through the aperture and a rod coupled to the shaft for rotation with regard to the post, the rod being of a length less than the post, the rod having a float ball at one end and an indicator arrow at the other end, and a threaded connector removably coupling the rod to the support bar for removal thereof; and a window formed in the side wall adjacent the pointer adapted to indicate the position of the pointer.