Geric -
SonarUnits.com potential sales value is hinged upon the need/neccesity for the industry to have a web presence. Now a days, you cant be in business without a site of some kind, but the issue here is why does a company who sells Sonar Units need a par/generic name and their branded company name?
At first I didnt think so, however reviewing how many companies and sites do sell Sonar Units, I believe you may actually find an end-user with this method. There is competition on the internet for this business and this is a viable keyword name. I dont believe its so generic its going to represent huge bucks, but I do believe you should be able to find $500-1000 for the end user, perhaps more if you can sell and market it properly.
Best of luck.