The Rotronic HC2A-AW series are high-precision digital probes specifically designed for measuring water activity (aw) in liquids, pastes, powders, and solid products. They are built upon Rotronic's advanced AirChip 3000 technology, which ensures exceptional measurement accuracy, long-term stability, and user-updatable firmware for future functionality improvements .

The probe delivers industry-leading accuracy of ±0.008 aw for water activity, ±0.8 %RH for humidity, and ±0.1°C for temperature. It operates over a temperature range of -40 to 85°C and is capable of the AW Quick function, delivering fast measurement results in typically 4-5 minutes .

Two interface variants are available to suit different applications. The HC2A-AW features a digital UART output with an HC2 connector for use with Rotronic handheld indicators like the HP23-AW or the HygroLab laboratory benchtop analyzer. The HC2A-AW-USB version comes with an integrated 3-meter cable and a USB-A connector, allowing it to plug directly into a PC for use with the HygroSoft software, creating a complete PC-based water activity measurement system . Both probes are supplied with a protective wire mesh filter with a pore size of 20-25 μm .

For accurate measurements, the probe is designed to be used with Rotronic sample holders. The WP-40S sample holder accommodates both shallow (PS-14) and deep (PS-40) disposable sample cups, which prevent cross-contamination and allow samples to thermally stabilize prior to measurement. The HC2A-AW features an IP65 protection rating, making it resistant to dust and water ingress in demanding laboratory or production environments .