Alternating Pressure Pump with Inflatable Pad Mattress SystemAlternating Pressure Pump & Pad System is a quiet, high capacity air mattress that puts out 4. 5 liters and a pressure range of 160 mm hg. Also has a long 9 foot power cord and built in bed mounting brackets to allow the power unit to easily hang on your headboard. The pressure pad is made with a tough heavy duty 16 gauge PVC material and inflates to the height of 2 1 2". The interlocking bubble cells exchange air every 5 minutes for ideal comfort.