Boya by-Wm5 wireless microphone is for use with dslr cameras and camcorders. The 2.4Ghz gfsk system result in strong anti-Interference, good security and stability. Two-Way communication, but only sound from transmitter can be recorded. The operation range is 60M without obstacle, 360 degree all-Round revolveis workable, the maximum distance can reach up to 80M. You can adjust the volume through vol+ and vol- volume control. The lapel clip makes it easy to carry. Specifications: rf modulation: gfsk (Gauss frequency shift keying) frequency band: 2.4Ghz (2405-2478Mhz) frequency response: 35Hz-14Khz3Db signal/Noise: 76Db or more distortion: 0.1% or less (32Î,1 khz,65Mw output) rf output level: 5 mw earphone output level: 32Î,65Mw reception sensitivity: -85Db +/- 3Db / 0Db=1V/Pa, 1Khz audio input connector: 3.5Mm mini jack operation range: 50M (164Ft.) power requirements: 3.0V dc (Two lr03/Aaa size batteries) consumption power: transmitter: 3.3V/110 ma receiver: 3.3V/100 ma battery life: transmitter: approx3.5 hours receiver: approx4 hours dimensions: transmitter: 60Mm x 86Mm x28Mm (W/H/D) (2.36 3.3 1.1 inches) receiver: 60Mm x 86Mm x41Mm (W/H/D) (2.36 3.3 1.61 inches) weight: transmitter: 136G (4.37Oz) (Without battery) receiver: 152G (4.89Oz) (Without battery)