SuperQuad has manufactured and sold about 300 of these handheld devices, which attach to the wheels. Users can propel their manual wheelchairs more easily, and brake them more effectively. Most sales of their product, called a Wijit, have been word of mouth. SuperQuad earned top honors in a recent competition for venture capitalists, and now is looking to raise millions of dollars to ramp up its promotion and manufacturing. With FDA approval and a string of patents, the company figures it can thousands more. It was founded by Brian Watwood, paralyzed in a bike accident 20 years ago.