Sonde, meaning probe or sensor in French is an apt name for these instruments. They measure and log data from up to 11 parameters simultaneously. Many of the sensor ports are interchangeable and can be modified based on a project's needs. Designed for harsh environments and long-term deployments, many of these sondes include an integrated wiper to minimize or prevent bio-fouling. Several sondes are compact enough to fit in 2 inch wells. YSI sondes will log data at programmable intervals and can be easily integrated with NexSens real-time data logging systems.