Brass, 3/8 in x 1/8 in Fitting Pipe Size, Reducing Adapter - 1DFY6|6-2 RA-B - Grainger
Amazon.com: VCE 1/4" to 1/8" Adapter, 3.5mm 1/8 inch Male to 6.35mm 1/4 inch Female Audio Jack Gold Plated Adapter for Amplifiers, Guitar, Home Theater Devices, Laptop, Headphones - 8 inch : Electronics
1/4" to 1/8" stereo adapter - Audeze LLC
Threading Adapter, G 1/4 Male to NPT 1/8 Female
1/8" Female NPT X 1/4" Push Connect Adapter - John Guest - Bulk Reef Supply
Amazon.com: SiYear 3.5mm 1/8 inch TRS Plug to 6.35mm 1/4 inch Jack and 3.5mm Female to 6.35 Male Plug Gold Plated Set Audio Stereo Adapter Converter for Headphone, Microphone (4 -Pack) : Electronics
Dirt Bike Handlebar Adapters 1-1/8" TO 7/8"
1/4" Male to 1/8" Female Adapter
Adapter 7/16-28 (m) to 1/8” NPT (f) – LockNLube
BrassCraft 3/8-in x 1/2-in Compression x Mip Adapter Fitting in the Brass Fittings department at Lowes.com
Williams Sound 1/8" Stereo Jack to 1/8" Mono Plug Adapter ADP
RPS Lighting Female 1/8" Mini to Male 1/4" Mono Adapter RS-8610
1-1/4" to 1-1/8" Headtube Headset Reducer / Adapter 1.25" to 1.125"