Amazon.com: 1/4" to 1/8" Adapter,6.35mm Stereo Jack to 3.5mm TRRS Male Audio Cable Connector Adapter for Amplifiers, Guitars, Pianos, Home Theater Equipment Etc. : Electronics
Female Pipe Reducer 3/8" to 1/4" Npt Adapter Coupler Brass Fitting Water Oil Gas | eBay
U.S. Solid Brass Hose Fitting, Adapter, 1/4" Barb x 1/8" NPT Male Pipe Fitting, 1/4"x 1/4", 3/8" x 1/4", 3/8"x 3/8",1/2"x 1/2", 3/4"x 3/4" - U.S. Solid
1/8" to 1/4" Stereo Adapter - Etymotic
Amazon.com: Viair 90001 1/8" Female BSP - 1/4" Male NPT Adaptor - 2 Piece : Tools & Home Improvement
3.5mm to 1/4 Stereo Adapter, 1/8 inch Female to 1/4 inch Male Aux Jack Converter Headphone Adapter - Black, 1PCS - Walmart.com