pH test paper Duotest pH 9.5–14.0, with two indicator zones, refill pack

Duotest indicator papers combine two different indicator zones on a single strip. The zones are separated by a hydrophobic barrier, which effectively prevents mixing of the reaction colors and increases the mechanical stability. The refill reels of indicator paper come singly sealed to ensure long-term stability and protection against many external influences. They have to be placed in the plastic reel with color scale to be used.