Thanks, I didn't know that, actually I'm looking to sell this one before I buy a different thru hull. I have two of the standard sihd's I bought this one because the HB site lists this as the only thru hull that matches up by on the forums I hear that may not be true. I just wanted something to shoot the bottom while underway, then when I slow I'll switch to the transom mount SI. My plan was to raise it just a bit to get it out the the water while on plane so I dont get any spray... thanks again for the correction