Headphones Adapter for Piano Keyboard, 2-Pack 3.5mm 1/8'' Female to 6.35mm 1 /4'' Male Jack Plug Stereo Adapter Gold Plated for Electronic Piano, Guitar, Drum - Walmart.com
Amazon.com: tisino 1/4 to 3.5mm Adapter, 1/4" Female to 1/8" Male Stereo Audio Adapter for Headphone, Amplifiers, Guitar, Amp etc. - 1ft/30cm : Electronics