2 Sennheiser XSW 12 Wireless Systems (Frequency: 542-578 MHz) with 2 Lavalier Microphones and Sennheiser Rack Mount Kit 960 tunable frequencies across 24 MHz, to avoid interference Dynamic cardioid lav microphone included Up to 10 hours of operation using 2 AA batteries Frequency: 542-578 MHz INCLUDES: GAM3 rack Mount