Humminbird AS 360SSI 360 Sonar Transducer 408310-1 Similar to radar which is used above the water Humminbird's 360 Imaging® provides a complete around-the-boat underwater image with the same sharp detail anglers have come to know with Side Imaging® technology. With a single sweep 360 Imaging® has the ability to cover a 300-foot diameter circle or a segment from 10-180 to view a specific area. This optional accessory does not replace your standard SI transducer it enhances your product and is controlled directly from any compatible Humminbird unit. (Units with side imaging® and an ethernet port. Older models may require a software update.) You must use a standard transducer in order to have a digital depth reading. May be mounted directly to a flat transom. Optional jackplate and outboard engine brackets available.