I used the interphase color twinscope for several years. I had several issues. I used the transom mount ducers. There are two and they are about the size of a baseball. It was a challenge getting them in the right location. The performance was great, under the right conditions. Your range is about 4x water depth. So, to get out to 1200 feet like they advertise, you need 400 feet of water. Sea conditions effect the performance a great deal. On a perfectly calm day out in 80 to 100 feet I had good performance. When it kicked up to three or four feet the performance was not so good. The display resolution and presentation was not as good as it should have been, it was pixeled or blocky. Performance offshore was even worse, due to sea conditions. Riding up and down the waves continuously changes the xmit/receive angle relative to the water surface which I feel affected performance. On several occasions in the Bay I was able to track a school of bait when boat pressure pushed them down and we were able to stay on target. I was NEVER able to do this offshore. I also found myself spending too much time focusing on the electronics and not what was going on around me. The unit was replaced after two seasons.