This Siemens Maquet Adult Ventilator Test Lung 190 is a high quality 1 liter restrictor test lung. This test lung is the Siemens Adult Test Lung 190, part number 6006832, and is manufactured by Maquet. This test lung is considered the "gold standard" of test lungs because of it's durability. Great test lung for field checks and testing on ventilators and anesthesia machines. If you want a long lasting test lung, choose the Siemens Maquet Adult Test Lung. 15mm OD.