AP250 is specially designed to ensure quick and effective refraction on single click. Either 33 test charts can be chosen arbitrarily or the features of program can be used to prepare two charts sequences as per the requirement. Independent characters or vertical and horizontal lines can be isolated by users due to masking controls present in the device. Also, the user is capable of applying polarization filter or red/green filter to all charts. The product provides fast and simply adjustable focusing controls which enable users to finely focus slides having distance of projection 10 to 26.5 feet. With a halogen bulb of life 2000 hour, it provides bright and glowing slide images.