ADVANCED: US-B1: Under sink filtration system, capable of full flow to existing faucet (not included). Same performance as US-A1, PLUS: 99.99% reduction of common water-borne bacteria1, mold spores2, algae2 and parasitic protozoan cysts3. 2,000 gallons and 1.5 GPM flow rate. Tubing and fittings included.