Thanks for asking...great piece of test equipment. Very easy to use. We have learned a lot this winter with this DO meter!! I am focusing on what I term "intermittent cycle aeration" and couldn't do the science/product development without it. Monitoring DO in 7 ponds across the state.

The first DO unit I bought (the one pictured) was through one of YSI distributors. Not going to use names. Short story..I brought it out into the field and the handheld wasn't communicating with the probe. No problem. I get home and call YSI. They tell me the unit is 3 years old! I sent it back to the distributor got my full refund. Then went to YSI to purchase a new unit. Frustrating to wait the extra week but all good in the end.