The EZ DPD™ dispenser from IDEXX Laboratories Inc., of Westbrook, Maine, makes residual chlorine testing easy. It allows sample collectors to dispense a pre-measured dose of reagent with the press of a button, eliminating messy powder handling and leftover foil pouches. Refill vials screw on easily and quickly. The dispenser works with a wide range of color cubes, color wheels and colorimeters. Color-coding distinguishes free and total chlorine tests.