Humminbird XFM 9 20 Plastic Flush-Mount Thru-Hull Transducer<div style="text-align: left;"><strong>[Product Information]</strong><br><ul><li>Thru-hull， flush-mount transducer， works with thinner hulls， while internal， steel sleeve provides extra reinforcement</li><li>Dual-beam， with 20-， and 60-degree beam angles and operating frequencies of 200 kHz and 83 kHz</li><li>Not recommended for trailered boats， and professional installation recommended</li><li>Compatible with many of Humminbird's Piranha， Matrix and numbered series sonar systems</li><li>Doesn't require a fairing block， and is backed by manufacturer's one-year limited warranty</li></ul></div><img src="http://ecx.images-amazon.com/images/I/41vCghM-NdL.jpg" noproxy>