The 515 CLQ make plotting quick and easy no matter which type of topographic map you are using with its 1:24,000, 1:25,000, and 1:50,000 scales. All scales come in two colors, so they are easy to read. The 515 CLQ also offers a large sighting mirror with a 'V' notch, so you can take readings on distant landmarks. A geared declination allows adjustment for the difference in degrees between magnetic north and true north, giving you a faster read and reducing chance of error.