I had a guy in New Jersey that I was getting these from but he has gone out of business. There is a guy on ebay selling the same 1. These are the same thing that they use in the stores to power the demo's. I have 1. They already have the humminbird plug on them. they are cheap. about $15.00 with ship'n. Just plug it in and play. Make sure you have the plug turned right or it won't work. If it doesn't work turn the plug over.

AC power supply for Humminbird Locators, - eBay (item 200446596983 end time Oct-30-10 20:01:03 PDT)