Great for when you can't reach under the deck, TRAC Isolator Bolts let you install your anchor winch, trolling motor, and other accessories from the top of your boat deck. Bolts are marine-grade 316 stainless steel for the ultimate in corrosion protection in fresh and saltwater. Unique design helps protect your boat from vibrations. Easily installed in a 1/2" hole with Phillips head screwdriver. Use with any accessory with up to a 1-1/8" thick frame.