MVG's EME Guard XS 40 GHz is a monitoring device made for people who work near antennas. It continuously scans for electromagnetic waves and alerts users whenever the acceptable limits have been exceeded. It features accurate measurements, tri-axis sensors and instant audio and visual alarms in a user-friendly design. Product configuration: MVG case, wrist strap, lanyard, connecting adapter, and armband. There are two (2) 1.5 V size N alkaline batteries included. Measurement Capabilities: tri-axis sensors, instant audio and visual alarm triggered when EMF exceeds the reference level.