These liter reservoirs feature a female Luer side drain, Radnoti Quick Disconnect fittings, and 28mm threaded-top closure. A second reservoir can be used in experiments on hypoxia or for the addition of modified media or drugs if the experimental protocol precludes the use of the injection ports available in our heart perfusion system. In addition to its use for isolated heart preparations, these reservoirs are ideal as a source of aerated solutions for organ baths or gassed solutions used in certain HPLC procedures. To maintain hydrostatic pressure, two reservoirs may be used, one slightly higher than the other so that by siphon action the higher reservoir will feed the lower reservoir and thereby maintain a constant level using a bubbler with fluid inlet port described below. Constructed of borosilicate glass.