Amazon.com: JOMLEY 1/4 to 3.5mm Adapter, 1/8"(3.5mm) Female to 1/4"(6.35mm) Male Adapter, Quarter inch to 1/8 inch Stereo Headphone Adapter, Amp Adapter - 2 Pack : Electronics
1/4'' to 3/8'' screw thread converter-adapter | TeleprompterPAD.com
Amazon.com: NANYI 1/4 Inch Female to 1/8 Inch Male Stereo Headphone Adapter, Upgrade 6.35mm Jack Stereo Socket Female to 3.5mm Jack Stereo Plug Male for Headphone, Amp Adapte, Black 1-Pack : Electronics
Parker - Industrial Pipe Adapter: 1/4″ Female Thread, 7/8-14 Male Thread, Male Straight Thread O-Ring x Female NPTF - 09107947 - MSC Industrial Supply
LTWFITTING 1/4 in. FIP x 1/8 in. MIP Brass Pipe Adapter Fitting (5-Pack) HF1024205 - The Home Depot
Proline Series 3/8-in x 1/4-in Compression Adapter Fitting in the Brass Fittings department at Lowes.com