This is a Perko Thru-hull strainer made from cast bronze with machined slots. We offer this product in 4 different sizes, which are listed below with their part numbers. Made in the USA. 0066DP1PLB - 3.50 x 2.50" Size - fits 0.375 - 0.50" thru-hulls 0066DP2PLB - 5.00 x 3.25" Size - fits 0.50 - 1.00" thru-hulls 0066DP3PLB - 6.25 x 4.25" Size - fits 1.00 - 1.50" thru-hulls 0066DP4PLB - 8.00 x 5.125" Size - fits 1.50 - 2.00" thru-hulls