The AP-2 HM smart EC pen is a portable 2-in-1 water quality detector that simultaneously tests EC value and liquid temperature, built with high-precision sensor to deliver ±2% accurate data within 0–9999µS/cm measuring range. Equipped with ATC automatic temperature compensation, it eliminates reading errors caused by fluctuating water temperature, supporting quick one-button digital recalibration without extra tools. Its large dual LCD screen displays two sets of data clearly, paired with practical data hold, auto power-off and low-battery reminder functions for user-friendly daily operation. Crafted with splash-resistant white ABS shell and patented magnetic adsorption design, it can stick on refrigerators for convenient storage, plus a protective probe cap to prevent sensor damage. Compact lightweight pen shape fits on-site sampling, widely applied in hydroponic planting, aquarium care, drinking water filtration, swimming pool maintenance and lab liquid testing. Pre-calibrated before delivery, it comes with matched CR2032 battery and storage case, an ideal compact testing tool for household growers and professional laboratories.