The sound is good but its scope is very limited (no better than infrared headphones); compared to a Sennheiser RS4200 helmet, I would say a stave divided by three when you leave the room. The function to listen to the environment by pressing the front button is not used much as a deaf can not hear the TV if the key is pressed. Reading the technical information on the manufacturer site, it says two AAA rechargeable batteries. Which suited me well but in reality it is rechargeable battery house that I have not found any renewal. So back to Germany with costs 16.15 euros return and refund of 101.96 for an initial expenditure of 105.95. All the shipping cost is 20.14 for me despite the seller's promise (SOTEL-GMHB) to reimburse me 8 over these charges. I made the mistake of telling them I was unhappy. supporting evidence.