What’s that powdery substance inside the container that came with my kit?

The powdery substance in the white jar is an absorbent material. In the off-chance that there’s a spill during transport, it prevents the reagent from doing any damage to its surroundings. We include it as an extra precaution. You can also conduct your tests over the jar so that if a drop misses the testing vial, the reagent will land onto the absorbent material.