1.Headphone Adapter Set: 2 types of adapter are included, 6.35mm (1/ 4 inch) male to 3.5mm (1/ 8 inch) female and 3.5mm male to 6.35mm female. 2.6.35mm male to 3.5mm female adaptor: amplifiers, electric guitar/piano, stereo system, home theater devices or AV receivers with a 6.35mm stereo jack. 3.3.5mm male to 6.35mm female adapter: suitable for a 3.5 mm (1/ 8 inch) stereo port to accept a stereo cable (such as 6.35mm headphones) with a standard 6.35 mm (1/ 4 inch) plug. 4.Gold Plated: Connector audio Gold-plating resists corrosion , durable and anti-rust, resists corrosion, ensures minimal signal loss. 5.Special design: 360 degree grip treads help easy plugging and unplugging, do not need to distinguish the positive and negative side, convenient to use. 4PCS headphone adapter in total in 2 types, each type has 2 pieces.