Check the listing for details. attwood 4801-7 Automatic Bilge Switch, 12-Volt, 15 Amp Maximum Pump Amp Draw,.... Color: Unspecified, Condition: New. Listed at 69.35 USD. This S3 Series switch incorporates proprietary Electronic Sensing technology for the most precise operation, and it is engineered to operate in any bilge water mixture consistently without failure. The pump won’t be exposed to continuous cycling as the switch can easily distinguish splashing bilge water, chemicals, sludge build-up, or foam.