This Attwood Bronze Garboard Drain Plug reliably provides bilge drainage when hauling out, and it seals securely when not draining. It has machined and tapered pipe threads to ensure a watertight plug fit, and the nut can be removed with a wrench or pliers. This drain plug has a 3/8-inch neck depth and a ½-inch NOT drain. It installs easily and securely using #8 screws in 3 countersunk holes. Attwood Corporation has been an award-winning leader in engineering, testing, and manufacturing the highest quality marine products for over 100 years. We deliver safe and reliable lighting, fuel systems, water systems, seating & pedestals, swim ladders, custom upholstery, and general marine accessories that are easy to install and meet regulatory compliance.