The G-100+ Custom Built Cushion is an alternating air pressure flotation seat cushion designed to prevent pressure sores for people with lower extremity or mobility disabilities, spinal cord injury and others who use a wheelchair. This system features computer controlled pressure management that increases and decreases air pressure in the cushion as needed. Each cushion is custom built to fit the user and wheelchair. POWER: Uses rechargeable nickel metal hydride batteries with a life expectancy of 7 years and with 100 hours plus running time on one charge. An indicator light goes on when a recharge is needed, and there is an audible warning when the unit is running on reserve power. WARRANTY: 2 year warranty.