Features and Benefits: For extremely dry compressed air producing -30 degree F. dew point Sight glass for indication of desiccant bead replacement, when beads turn from blue to pink replace Complete with initial desiccant charge PneuMasterAir 2552AW recommended as pre-filter for 3121 Made in the U.S.A. PneuMasterAir 3121 2-Quart Desiccant Dryer delivers extremely dry compressed air producing -30 degree F dew points without electricity or refrigeration. Sight glass in the bowl indicates when the desiccant beads turn from blue to pink, then simply replace with new beads. Initial supply of desiccant beads included. PneuMasterAir 3006 quart size replacement desiccant. Recommended PneuMasterAir 2552AW oil removing filter in front of 3121 Desiccant Dryer to protect oil from contaminating the desiccant beads. Max flow 30 SCFM, 1/2" NPT inlet and outlet.