The serial number format matches their RMA info page, so I've requested one. $120 is much better than a new one, and I don't need this one for a while....next trips are recreational and one transmitter ( i still have two working out of three) will be fine. Thanks, Craig.I'm not really sure if you don't know it's origin. You could go to the Huish return portal and try the serial number, you have nothing to lose. I've had very good service from Huish, unlike others on SB.