Pentek SH144376 White RO Membrane Housing for standard RO Membranes. The RO Membrane Housing can be used with most 11.75-inch to 12-inch reverse osmosis membrane elements. This reverse osmosis membrane housing has a thicker body for stronger durability and stronger membrane cup design to prevent cracking. The RO membrane housing has three standard 1/8 threaded ports. If you do not have fittings, see the Instructions section for available fittings. You do not have to worry about bypass of Brine water to the Permeate side which is quite common on most other housings manufactured today. The reverse osmosis membrane housing has been Tested and Certified by NSF International to NSF/ANSI Standard 42 for material and structural integrity requirements only.