Use this device to collect water samples from any desired lake depth. You can raise samples to the surface, and make on-site measurements of dissolved oxygen, pH, temperature, or conductivity using Vernier sensors (sold separately) and a Vernier interface (sold separately) take some samples back to the school for testing. The Water Depth Sampler has a unique trigger mechanism that requires only one line to raise and lower the chamber and also to seal the 1.5-liter chamber. A 50-foot nylon drop cord is included.