MillSO 1/8 to 1/4 adapter is a 3.5mm Female jack into a 6.35mm Male plug adapter, for connecting smartphones, tablets, or headphones with standard 3.5mm plugs to audio devices with a 6.35mm stereo jack. The plugs and sockets snap in very well. Do not too loose or too tight so you can enjoy high-quality sound. 6.35mm Male Adaptor is compatible with amplifiers, electric guitar/piano, stereo system, mixing console, home theater devices, or AV receivers with a 6.35mm stereo jack. 3.5mm Female Stereo Adaptor is compatible with smartphones, MP3 players, Tablets, portable CD/DVD players, or laptops with standard 3.5mm 1/8 inch plugs.