What brand is it.
Tim's link goes to Raymarine, unfortunately the page shows the part out of stock and no price is displayed.You should call the manufacturer of the unit and tell them what you need. If it's an older model you might have some problems. In my case, I had a broken cup on the anemometer's wheel. The unit was a Standard Horizon WS1, which looks EXACTLY like the WS45. What I found out was the WS1 was made when the company was in England. They sold the company to an American firm, and CHANGED the way the wheel mounted to the sensor. Of course, they had long since exhausted the old WS1 replacement parts inventory. In addition the wiring was changed, so purchasing a complete new transducer for $400 would not work with the old display. The service technician's suggestion was to simply buy a complete, new unit.....not what I wanted to hear. Anyway, I ordered a replacement tri-rotor, hoping I could modify it to mount on the existing transducer. The part only cost $15, and I figured...what the heck? Upon examing the new part I could see the difficulty in modifying the hub/axle connection. The backup was to try fusing a new cup to the old wheel. So down to the boat I went to remove the old unit. Unfortunately, a friend of mine offered to go up the mast and, in his effort to remove the unit from the masthead, dropped the whole thing. It bounced off the deck, breaking the windvane, then kerplunked into the 20 ft deep, moss-bottomed bay. Now I have no wind speed or wind direction. But.........actually it has not been a disaster. I bought a hand held wind meter for $80, and installed a pair of mini vanes on the shrouds. Now, I no longer stare at the wind direction display but use my senses to sail and trim. I think I've become closer with the boat without the instrument. I still plan to replace the unit, probably with the less expensive Navman, but its absence has not detracted from my sailing pleasure.