Wireless headphones compatible with the following metal detectors: Nokta Makro Anfibio, Kruzer, Simplex and RACER 2: SYSTEM BOX SERIAL NUMBERS BIGGER THAN 9402 GOLD RACER: SYSTEM BOX SERIAL NUMBERS BIGGER THAN 6916 IMPACT: Software version R2_V1.16_V1.14 or later versions. You can download the latest software version from http://noktadetectors.com/onlineupdate_impact-metal-detector.asp