Sounds like you have a very valid concern. They are a very good and expensive water detector but I read the following review that would sure make me hesitant to buy one where you are located.
I have a bad experience with the Fisher Lab's service. My only one CZ-20 was broken down in September, 2007. I contacted the dealer in Thailand that I bought the detector from. He's a nice guy, actually. It later was sent to the Fisher Lab in USA. I was informed after one month pass by that the cost of fixing is $US 928.77, including freight and labor cost. It's costly, isn't it? The point is that I think the Fisher Lab is tricky. They don't mean to give you CZ-20 service anymore. They want to sell the coming CZ-21 rather than fixing the old model, CZ-20. So, they charge you so higher that you can do nothing, but you are forced to buy the new one. This is the way company cheats you. Next time if you want to buy a new metal detector, I want to remind you that think over the good service, rather than the new body cover of the CZ-21 There are many brand names and types of detector at the moment. Make sure you get new one with a good service. Fisher Lab is not providing you good service anymore, I bet!.