This Twist-Off Purification System is the ultimate “user friendly” filter on the market. Replacement of the cartridges is completed in a matter of seconds. You just detach the filter body from the permanent head with a twist of the wrist. The new filter cartridge is just as easily replaced by threading it into the head. The Twist-Off system automatically turns the supply water off when the cartridge is disconnected from the head. No drips. No hassles. This purification system is independently certified to remove the things most people are concerned about in their tap water: chlorine and other harmful chemicals, lead, bad taste and odor. However, this commercial-grade purification system leaves the beneficial minerals in your purified water. Small offices and homes only need to change the filter cartridge once a year. Medium-sized offices (more than 30 people) and water coolers that get lots of use will want to change the water filter cartridges twice a year.