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
M6x1 (m) to 1/8" NPT (f) Adapter for Grease Fittings – LockNLube
Amazon.com: Legines Brass Pipe Fitting, NPT Adapter 1/4" Female to 1/8" Male Reducing Adaptor 1200psi High Pressure (Pack of 2) : Industrial & Scientific
1-1/8" to 1" Headtube Headset Reducer / Adapter 1.125" to 1"
Amazon.com: NANYI 1/4'' Male to 1/8'' Female Stereo Headphone Adapter Connect Cable, Upgrade 6.35mm Jack Stereo Socket Male to 3.5mm Jack Stereo Plug Female for Headphone, Amp Adapte, Black 1-Pack : Electronics
Adapter Fittings 1/8 NPT to 3/16 4pk | Allstar Performance
Amazon.com: KOOTANS 1/4 NPT x 1/8 NPT Male Solid Brass Nipples, Heavy Brass Pipe Adapter Fittings Hex Reducing Nipples Connectors 4Pieces : Industrial & Scientific
Amazon.com: Cable Matters 5-Pack 1/4 to 1/8 Headphone Adapter (3.5mm to 1/4 Adapter, 6.35mm to 3.5mm Adapter) : Everything Else
Bsp-npt Adapter 1/8" Male Bspt To 1/4" Female Npt Brass Pipe Fitting Euro To Us Pressure Gauge Adapter - Pipe Fittings - AliExpress
Threading Adapter, NPT 1/8 Male to G 1/4 Female
LTWFITTING 1/4 in. O.D. Comp x 1/8 in. MIP Brass Compression Adapter Fitting (5-Pack) HF684205 - The Home Depot