Hach 2507200 pH Buffer Solution Kit is a convenient 3-Pack of color-coded pH buffers in 4 Liter (1 US Gallon) bottles.These pH buffer solutions are accurate to ±0.02 pH units. They work with any make and model of pH meter,
Red: pH 4.01
Yellow: pH 7.00
Blue: pH 10.01
33% Cost Reduction over single bottle purchase when purchased as a pH buffer solution kit.