The Extech 407123 is a heavy duty hot wire thermo-anemometer designed for accurate air velocity measurement in HVAC ducts, small vents, and other confined spaces. Its telescoping probe extends up to 7 feet with cable, allowing easy access to hard-to-reach locations without the need for ladders or scaffolding.

The instrument features a super large 1.4‑inch (36 mm) dual LCD display that provides clear visibility of air velocity readings. Velocity measurement range covers 0.5 to 45 mph (with equivalent units available), making it suitable for a wide variety of ventilation and airflow applications.

Field‑friendly functions include Max/Min recording to track fluctuations and Data Hold to freeze readings on the display. For advanced data analysis, optional data acquisition software can be purchased separately to log and graph measurements on a PC.

The 407123 ships complete with the telescoping probe and cable, six AAA batteries, and a protective holster for safe transport and storage. Note that an AC adapter is not available; the meter operates solely on battery power.

Typical applications include:

• HVAC system balancing and troubleshooting
• Ventilation and exhaust duct measurements
• Industrial hygiene and indoor air quality assessments
• Cleanroom and laboratory airflow verification

Features

• Hot wire technology for accurate air velocity measurement
• Telescoping probe extends up to 7 feet with cable
• Air velocity range: 0.5 to 45 mph
• Super large 1.4" dual LCD display
• Max/Min recording and Data Hold functions
• Optional data acquisition software available
• Powered by six AAA batteries (included)
• Includes protective holster
• Ideal for HVAC ducts, vents, and industrial airflow monitoring