Couple this with your existing RO unit for ultra-pure water! Comes with clear housing, refillable mixed bed color changing resin cartridge, mounting bracket, screws, 12 feet of 1/4" tubing, and two 1/4" quick connect fittings. Refillable resin cartridge measures a standard 10" x 2.5" (nominal). 

The 10" x 4.5" and 20" x 4.5" configurations utilize an opaque housing and cartridge, and non-color changing resin.