Field-proven, the YSI 55 DO Instrument measures dissolved oxygen in mg/L or percent saturation. Offering push-button calibration with a built-in calibration chamber, direct salinity, and altitude compensation, the YSI 55 provides simultaneous readings of oxygen and temperature. Dissolved oxygen readings are automatically compensated for temperature. Also available is the YSI 55D with a detachable cable.

Looking for a rugged, field-worthy instrument for measuring dissolved oxygen? The new YSI 550A DO features a waterproof IP-67, impact-resistant case and innovative field-replaceable DO electrode modules. Measure dissolved oxygen and temperature simultaneously using YSI's proven polarographic technology for oxygen and YSI Temperature Precision TM thermistors, the worldwide standard for accuracy.

The YSI Salinity, Conductivity and Temperature Instrument is ready to use when you turn it on. A large, backlit display shows temperature along with conductivity, temperature-compensated conductivity, or salinity. In addition, the YSI 30 lets you set the reference temperature and the temperature coefficient if you're measuring temperature-compensated conductivity. The YSI 30 allows for user calibration for highest accuracy. Built-in storage chamber protects the probe when not in use.

Featuring breakthrough multiparameter monitoring, the YSI 85 Instrument offers simultaneous dissolved oxygen, conductivity, salinity and temperature measurement. Automatic function verifies that the system is working. The YSI 85D is also available with a detachable cable.

The YSI 60 measures pH and temperature at depths up to 100 feet. The replaceable, rugged pH electrode has a one year warranty. Tough, watertight case withstands the rigors of field work. Built-in storage chamber protects the probe when not in use.

Finally - a pH instrument- plus more - designed for field use! The handheld YSI 63 measures pH, conductivity, salinity and temperature with a single probe to depths up to 100 feet!

The replaceable, rugged pH electrode has a one year warranty. Tough, watertight case withstands the rigors of field work. Built-in storage chamber protects the probe when not in use. A bright, backlit display is easy to read. The YSI 63 pH instrument has memory for up to 50 readings.