Good for Reverse Osmosis Water Filter, Whole House Water Filter and RO DI Filter * Fits 10"x2.5 standard filter cartridges, compatible to most RO systems, includes Watts Premier, Flowmatic, PuROLine, Crystal Quest, Apec and etc * 1/4" Inlet/Outlet * Made of 100% high-quality polypropylene * Transparent housing makes it easy to judge the filter status