Like Superman, Airmar's new M256 and M260 transducers see clear through the hull. No need for an additional through-hull in the bottom to develop a leak. Airmar designed these 1kW transducers to function with most popular depth sounders of 300W to 1kW. In addition to eliminating another hole in the bottom, a transducer mounted inside eliminates the drag an external transducer creates, and its performance won't be affected by aerated or turbulent water. The company's liquid-filled mounting base conforms to almost any deadrise angle. The multi-element M256 delivers a 12dB gain over comparable single-element transducers, according to Airmar. To enhance the transducer's definition and performance at high speeds, the M256 has internal shielding against EMI/RFI interference and narrow beam widths at 50kHz or 200kHz. The standard M260 uses a transmission line and an internal diplexer for 50kHz or 200kHz. Prices: $585 to $860. Airmar Technology Corp., www.airmar.com.