These high precise test strips quickly measure water hardness, chlorine, and other vital parameters, delivering reliability result. Perfectly for home users, laboratory technicians, environmental workers, and anyone concerned with water quality monitoring. Suitable for a variety of applications including home tap water testing, swimming pool maintenance, drinking water analysis, and natural water body surveillances. With 50 pieces per bottle, our aquarium test strips offer long last peace mind, helping you maintain the perfectly environment for your fish and plant. Please note: the physical slightly color difference or difference, does not affect the use, please do not mind, thank you! Colour:As Shown Material:paper Package Contents: 50 * Aquarium Water Test Strips Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.