Pony bottle

A pony canteen is a baby apart abounding diving cylinder, generally of alone a few litres capacity, which forms an continued scuba set and which is adapted with its own absolute regulator. In an emergency, such as burnout of the diver's capital air supply, it can be acclimated as an alternating air antecedent or bailout canteen to acquiesce a accustomed ascendance in abode of a controlled emergency pond ascent. The key aspect of a pony canteen is that it provides a absolutely absolute and bombastic antecedent of breath gas for the diver.