High sensitivity sensing head using components and advanced technology, so that the penetration increased by several times, greatly improving the sound quality, carefully and slowly adjust the voice frequency, so as not to cause discomfort to the ear plugs. High sensitivity metal alignment with headphones improves sensitivity and sound quality, high sensitivity detects sound from wall, window, doors or armor plate with headphones for clear sound quality. 3.5 mm headphone jack can be connected to display spectrum, voice recorder, transmitter, wireless devices, etc. (not included), also can be plugged into the dual channel line for direct recording, can detect abnormal noises from heating ducts, fire ducts, water pipes, underfloor heating ducts, automobile, home plumbing, and more. Through wall door microphone with charging interface, the built in battery can be charged repeatedly, fully charged once available 5 to m7 hours, machine jack and upward switch knob, easy to use and adjust. Press firmly against doors, window and wall and adjust the sound with the knob until you hear a clear sound, able to emit sound from wooden wall, bricks, window and doors, effective noise filtering and faster sound detection. Color: Black Material: ABS Package Contents: 1*portable leak detector Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.