I have one hooked up to a DSI transducer and it fits pretty well. Didn't use the star shaped neoprene washer as it pushed the transducer past the hull. Pretty pricey for a bit of plastic, but its pretty hard to make a custom mount because of the need to fabricate the fingers to fit in the groove on the ducer.
IMG_0567 by
lipripper1, on Flickr
IMG_0568 by
lipripper1, on Flickr