These mulit-parameter test strips test for five water quality measurements on 1 strip: Free Chlorine, Total Chlorine, Total Hardness, Total Alkalinity, and pH (6.2 - 8.4). 50 test strips.
Rolling friction car kit, provides four cars for exploration into the force of friction, Each car provides a set of different material wheels (wood, fabric, soft rubber, soft silicone), Weight (lb): 1.0, Length (in):5.8, Width (in):6.5, Height (in):3.5