1. gain (dB): 120dB±3dB, suitable for moderate to severe hearing loss (see hearing loss chart) 2. Digital display rechargeable box charging: Your hearing aid can be with a detachable charging box. And there is a battery on the charging box to light up the display. (You need to charge the detachable charging box first.) It is easy to carry, saving you the trouble of constantly buying button batteries. You can intuitively see the remaining power, which is convenient to charge in advance. 3. Charging time: 2-3 hours of charging, can work for 30 hours, (faster charging than other charging boxes on the market, longer working time) The indicator light is red when charging. It goes out when fully . 4. Designed for people with hearing impairment, it fits the ear canal better. You not feel pain even if you wear it for a long time. Please Noted: Causes of whistling/noise: In order to make a small hearing aid, the internal amplifier and microphone are placed close to each other. The sound is continuously received and expanded, so there is a certain possibility of whistling after power-on. At present, small hearing aids and high-power hearing aids on the market are difficult to avoid whistling, and only fully functional digital hearing aids can avoid whistling. Product parameters: 0SPL 90(dB SPL):120±3dB HAF OSPL 90(dB SPL):110±4dB gain(dB):30±5dB HAF/FOG gain(dB):29dB Frequency range(Hz):320-4500Hz Equivalent input noise(dB):less than equal 30dB Total harmonic distortion:less than equal 10% Voltage:D.C.3.7V Current:less than equal 1.5mA Charging time(H): 2-3 Working time per charge(H): 30h Battery: Built-in lithium battery Current: 1.5mA Dimensions:15x10x20 mm Product name:ITE hearing aid Note:The product package does not include a plug. The product itself uses USB charging. Tips: 1. Clean the ear canal before use. 2. If you are not using the hearing aid, turn it off. 3. Charge it regularly to avoid the device running out of power. Color:White Material:plastic Package Contents: 2 * Wireless Hearing Aid 1 * Charger Case 1 * USB Cable 1 * English instruction manual 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.