Both the ribbed cap and the housing are one piece injection molded parts so no solvents or glues are used in the manufacturing process The ribbed cap incorporates acme square threads and two O rings to ensure a leak proof seal The RO Membrane Housings have a straight inlet and are equipped with 2 90outlets The 90 outlets eliminate the need for additional elbows All ports have standard 18 NPT threadsFits any 18 x 12 1812 RO membrane Additional Details ------------------------------ Product description: Both the ribbed cap and the housing are one piece injection molded parts so no solvents or glues are used in the manufacturing process The ribbed cap incorporates acme square threads and two O rings to ensure a leak proof seal The RO Membrane Housings have a straight inlet and are equipped with 2 90outlets The 90 outlets eliminate the need for additional elbows All ports have standard 18 NPT threadsFits any 18 x 12 1812 RO membrane