Global Model and limits for impurities such

and limits for impurities such as chloride

Demonstrate with the coil spring

🏗️Built for the Classroom: Designed specifically for preschool through 2nd-grade children

providing clear color changes for visual detection

easy-to-read digital LCD display and simple two-point manual calibration

Global Model and limits for impurities suchGlobal Model This model can be used as a visual aid in schools for Geology lessons. Premium Quality: This item is made of high quality, heavy duty and durable materials. Designed for use in geology classrooms, household and educational settings. If you need custom order with different sizes design, please contact us. Safely Packaged to avoid being damaged during transportation.