Wireless sports earphones featuring Air Conduction technology. I purchased these because I was interested in open-ear headphones, but I didn't like the feel after using them once, so I'm selling them. I remember buying them on Amazon for around 3000 yen. - Brand: MONSTER - Model: OPEN FREE AC100 - Type: Wireless Earphones - Included: Charging case, charging cable, instruction manual - Color: Black Thank you for looking.