An M.S.A. Mining Methanometer.
An M.S.A. Mining Methanometer type D6. Made from Plastic. Size 6″ x 2 1/2″ x 2″.
Used for checking for Methane Gas below ground. Used with an extension a telescopic extension probe and rubber bulb, the probe would screw into the top of the detector which is situated under the Yellow cap.