Especially for occasional measurements and hydrographical field surveys Observator offers many portable measuring instruments. These handheld devices are rugged, battery powered and available in a robust carrying case.

• YSI ProDSS: Multiparameter handheld meter with exchangeable sensors for many parameters; conductivity, dissolved oxygen, pH, algae, ammonia, chloride, nitrate and more.
• YSI ProSwap: Handheld meter for one exchangeable ProDSS sensor.
• YSI ProSolo: Handheld meter for (optical) measurement of dissolved oxygen.
• YSI Pro30 CTD: Handheld CTD meter for conductivity and temperature.
• YSI Pro20: Handheld meter for dissolved oxygen, either with Clark amperometric sensor or galvanic sensor or special BOD/CBOD sensor (Carbonaceous-Biochemical Oxygen Demand).
• YSI EXO: Multiparameter handheld meter series.
• Analite NEP-5000-LINK: Handheld turbidity meter with app control on smartphone.
• SonTek CastAway: Autonomous handheld CTD meter with internal data logger and display.