Just a quick email, to say thanks, following the chat over the phone, I took your advice and purchased the standard transducer. Your advice saved me a packet, and on fitting up the new transducer; it gave me a chance to check out the old one, and yep, a hairline crack at the rear, and along the seam. Thanks guys, your honesty may have missed you a more expensive sale, but gained a loyal customer, who recommends you to everyone.