Aqua-Pure AP11T / AP11S and the CUNO CFS11T (# 55588-02) / CFS11 S (55588-02) models include a pressure relief button and are made from FDA CFR-21 Compliant Materials. The "T" and "S" suffix designates either a Transparent (clear) or Solid (opaque) sump housing. Includes AP110 5 micron grooved sediment filter and filter wrench.