3.5mm Stereo Jack Male to 6.3mm Stereo Jack Female Adapter - from LINDY UK
6.35mm Plug to 3.5mm Socket (Pack of 2) 1/4 to 1/8 inch Stereo Audio Jack Adapter | Converts Audio from Amplifiers, Guitar, Piano, Drums, Speakers & Mic that use 6.35mm to 3.5mm