This is a Puritan Manual Resuscitator manufactured by the Puritan Corporation in the 1970's. It used a black rubber mask which required the used to ensure that the mask seal was properly inflated with air using their mouth to blow into a small attached tube. Supplemental oxygen could be added to the green nipple port using connector tubing. It was not designed to be disposable as today's bag/valve/mask (BVM) one-use only manual resuscitators.