The following review was written by the editorial department of Chesapeake Bay Magazine.

Humminbird's new 500 Series comprises nine depthsounder/plotter models featuring 41/2-inch displays in either color or 12-level grayscale, with 200 to 250 watts of output power (RMS). The top-of-the-line 597ci combo ($570) offers an internal GPS antenna, built-in charts, a detailed color screen (640-by-480 pixels) and a 200/83 kilohertz transom-mount transducer. The economic 525 ($130) features a 240-by-240 pixel display, 12-level grayscale and 200 watts of power with a single-frequency 200 kilohertz transom-mount transducer. In between are seven color and grayscale combinations of fishfinder and plotter units. Humminbird, 800-633-1468;

April 2010