PUR PLUS FM4000B 3-Stage Faucet Mount Water Filter

PUR PLUS FM4000B: 3-Stage Faucet Filtration

PUR PLUS adds a third filtration stage to their standard FM-2000B faucet filter: a mineralclear stage that reintroduces beneficial minerals (calcium, magnesium) after the carbon filtration step. Standard carbon filtration does not selectively remove minerals -- the mineralclear stage is a marketing distinction over the two-stage unit. The functional difference is subtle taste improvement, which PUR quantifies in a panel taste test study available on their website.

NSF Certification

The FM4000B carries NSF 42 and 53 certification through the PLUS version filter (RF9999EL) -- reducing chlorine taste and odor, lead, trace pharmaceuticals, and industrial chemicals including atrazine and benzene. The PLUS filter also reduces mercury, which is absent from the standard PUR filter certification.

LED Filter Indicator

A three-LED indicator on the housing (green/yellow/red) tracks filter life. The indicator connects to an internal flow meter -- not a simple time-based countdown -- and changes state at 50% remaining (yellow) and 5% remaining (red). The indicator runs on a single CR2032 coin battery (5-year life).