These Bronze Groco strainers have robust slotted screen. A unique access door allows a diver to easily clear debris and marine growth in water or access thru-hull during haulout without removing hull strainer. This solves the common problem of inaccessible excessive growth that hampers performance and even causes premature failure in water pumps and exhaust systems. Eliminating the need to haul boats out of the water, these strainers can save enormous amounts of time and money. Available in various sizes to suit a wide variety of vessels. Bronze is the best choice for wood, fiberglass and steel hulled vessels. Aluminum vessels should seek aluminum strainers instead.