The YJACK FLOW Wireless Anemometer by YELLOW JACKET® includes an interchangeable, telescopic 18” wand for residential and small commercial systems. For larger systems, users can easily change to the 36” wand (PN 67082 sold separately) without the need for calibration. This lightweight, compact anemometer includes a convenient multi-point magnetic mount to secure the probe in ducts for hand-free monitoring. The YJACK FLOW Wireless Anemometer comes complete with a protective carrying case and two 1.5V AAA alkaline batteries.