So I found out, after I purchased, that these switches are not waterproof. Not a huge problem, except, if you read up on users experiences with them, you'll find out that over the years the spray gets into them. The spray will corode the switch terminals and leave you stranded. I ended up ordering a Blue Sea Systems 9001e. It's not only water proof, but you don't have to put the batteries in parallel on your way to putting the second battery on. If your main battery has a shorted cell, on your way from "1" to "2", you'll cross "ALL". "All" will effectivly put the shorted cell in your main battery across the terminals of your second battery. High current and heat WILL follow. The 9001e doesn't work this way and it's waterproof. Your call.
Rating: [3 of 5 Stars!]