Maximum sound output: 127 ± 4 dB Maximum sound gain: 48dB ± 5dB Harmonic wave distortion: ?5% Range of frequency: 250 ~ 3800 Hz Input noise: ? 30 dB Battery: Lithium battery Operating voltage: dc 3.7V Work current: ?4mA Color: as shown in the picture Size of the article: 4,35 * 2, 0 * 1.3 cm Package size: 15.3 x 9.6 x 3.8 cm Note: Adjust the volume at minimum before wearing. Choose a slightly larger ear plug to avoid whistling. If you hear a howl, check the ear (silica gel) is appropriate and if the Socket size is waterproof, the appropriate choice of earplugs and clogged, make sure there is no air leak. Keep the ear plug clean Remove the battery if you do not use it for a long time s.
Trustpilot
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