The boya uhf dual lavalier microphone wireless by-wm8 pro-k1 is a wireless microphone set, which is ideal for interviews, eng/efp, movie productions and more. the by-wm8 pro-k1 is an upgrade of the by-wm6 and by-wm8 wireless duo-microphones. the pro-version, for example, has a much lower distortion rate, which means that the sound is less distorted. this has significantly improved the sound quality. the set is also lighter in weight than its predecessor. Both the transmitter and receiver use two aa-batteries (not included). this allows you to use the microphone set for up to 6 hours. the by-wm8 pro-k1 has a maximum range of 100 meters, if there are no obstacles between the transmitter and receiver. you can also add a second transmitter later (see optional accessories). the by-wm8 pro-k1 can be used with dslr-cameras, camcorders and audio recorders. in addition, a smartphone adapter (see optional accessories) allows you to easily connect your mobile phone to the receiver. the wireless frequencies are 556.71 mhz-575.98 mhz and 576.39 mhz-595.66mhz. Usage boya by-wm8 pro-k1 The interviewee wears the microphone and transmitter, the latter can be attached to the belt using the clip provided. the receiver is connected to your camera by a cable. to mount the receiver on your camera, the receiver has a hotshoe connection. this connection has a 1/4" female thread, so that the receiver can also be mounted on a tripod. the receiver also has a headphone output, so you can listen to the recorded sound in real time. System specifications: - channels: 48 - frequency response: 40hz-18khz (+/-3db) - max. range: up to 100 meters (without obstacles) - operating temperature: -10 to 50 degrees celsius Transmitter specifications: - rf output level: 10 mw - audio input connector: 3.5mm jack plug - reference audio input level: -60dbv - input frequency range: 20hz-20khz - distortion: 0.5% or less - power supply: 2x aa battery (not included) - max. consecutive service life: 6 hours - dimensions (h x w x l): 208x67x29 mm - weight (without batteries): 80 grams Receiver specifications: - audio output connector: 3.5mm jack plug - signal to noise ratio: 70 db or more - distortion: 0.5% or less - headphone output level: 30 mw - audio output level: -60 dbv - power supply: 2x aa battery (not included) - max. consecutive service life: 4 hours - dimensions (h x w x l): 208x67x29 mm - weight (without batteries): 90 grams Lavalier microphone specifications: - transducer: condenser microphone - directional characteristic: omnidirectional - frequency range: 35hz-18khz - signal to noise ratio: 74 db - sensitivity: -30db +/- 3db / 0 db = 1v / pa, 1 khz) - connector: 3.5mm mini plug - length: 1.2 m To conserve battery life, you can turn off one channel when using only one transmitter.