Featuring our Patented S-Shape Seating Frame, the S-Ergo series is the original and authentic Ergonomic wheelchair in the wheelchair industry. Aircraft grade aluminum is the primary frame material which boasts a limited lifetime warranty, and 1 year on parts. The S-Ergo series feature Ergonomic design on the seat, backrest, armpads, brake handles, and handrims. S-115 series specifically feature removable and height adjustable footrest, breathable seat and back mesh upholstery, removable seat and back cushions, push to lock brakes with built in 2" extension, and a super compact folding frame for ease of travelling.