Unlike other alternating pressure mattresses, the PressureGuard APM does not create extreme pressure gradients between inflated and deflated cylinders. On top, the Geo-Matt anti-shearing surface forms a comfortable, therapeutic interface between the air system and the user. It absorbs and smoothes sharp pressure drop-offs that other surfaces can't, while the air system does the heavy lifting below, alternating weightbearing across the surface in ten-minute cycles. Six cylinders are programmed to inflate/deflate in a four-up-two-down pattern, ensures maximum patient support throughout the cycle. FeaturesCover The bacteriostatic top fabric is fire resistant, fluidproof, tear resistant, cleanable, and replaceable. The pleated design allows full integration with the mattress's Geo-Matt style shear-relieving surface while minimizing hammocking.Foam Topper The exclusive Geo-Matt style foam topper is a high density, medical grade foam. The unique geometric design consists of over 800 individual cells, each of which acts individually to redistribute pressure, to reduce heat and moisture buildup on the skin, and to reduce shear to underlying tissues. This foam topper is 2 in height and includes the unique Heel Slope feature, designed to further reduce pressure for the sensitive heel areaSafety Edge Bolsters The patented Safety Edge consists of a firm 2-part foam bolster whose inner edge contours under pressure to direct the patient towards the center of the mattress. This adds to patient stability in sitting and lying down, and helps prevent falls and entrapment between the siderail and the mattress.Air Cylinders The inflation system consists of six urethane air cylinders that run head to foot underneath the body and the foam topper. These cylinders perform the alternating pressure therapy, Cylinders inflate and deflate in a fixed 10-minute cycle. Inflation levels are designed to provide and maintain low interface pressures throughout the mattress, and to redistribute peak interface pressure points during the alternating cycle.Control Unit Features eight electronically-controlled comfort settings, programmable cycle times of 20, 25, 30, or 35 minutes and low pressure indicator with audible alarm SpecificationsWeight limit 750 lbsPump Conforms to UL 60602-1, CAN/CSA C22.2 NO.601.1Warranty 18 month warranty 1 Each / Each