Hands-free earphones with volume control, convenient for a specific terminal type. - Type: Hands-free earphones - Connection terminal: Specific terminal type - Volume adjustment: With volume adjustment function Thank you for viewing. I believe it was made by Monotaro, and I used it with the company phone. The carrier was au. I stopped using it when I switched the phone to a smartphone and it has been stored in a drawer for a long time. It is unknown whether it is still usable.