Wellhouse - Float Switches
Made by PKP www.pkp.eu
Available for about $45 from:
Chuck Hixon chixon@pkp.eu
Also from: http://www.clarksol.com/html/prodspecsFS00Z.cfm#purchase
The double throw type provide more flexibility as they can act as normally open or normally closed, but their current rating is not as great so they may wear out quicker. I brought one of each type.
Here is a lower priced alternative...