When HANNA® introduced its first version of the pHep (pH electronic paper) in 1986, it immediately revolutionized the standard in pH measurement. pHep's ease-of-use in combination with its affordability made it possible for non-technical and technical personnel alike to measure pH on the spot, accurately and inexpensively throughout a variety of industries. Since its introduction, over 1 million pHeps have gone to satisfied customers around the world.

The pHep 4 include features such as a dual-level LCD, battery level indicator, replaceable pH electrode cartridge, instability indicator, automatic shut-off and automatic calibration all in a floating, waterproof casing.