Omnipure offers you the best inline water filters in the world. The Omnipure K2533BB improves the taste for your drinking water, pure and simple. Great filter for icemakers, refrigerators and as a postfilter for Reverse Osmosis Systems. The Omnipure Inline GAC Filter Cartridge fits standard 1/4-inch water lines. The filter uses Granular Activated Carbon to remove contaminants for up to 12 months. 1/4-inch straight female thread fittings on both ends.