The durable Precor RBK 600 Line recumbent bike is equipped with a generously cushioned seat with a medium Air Flex seat back and a 500-watt single-stage drive system to ensure challenging but comfortable rides for years to come. To reduce pressure on your knees, Precor designed the recumbent bike to mimic the natural pedaling mechanics of our upright bike. By setting the seat rail at a precise offset from the crank, pedaling becomes more efficient while minimizing stress on the knees.