Amazon.com: 1PC 12AX7 ECC83 TO 6N2 6H2N 12AX7 TO 6N2 vacuum tube adapter socket converter : Musical Instruments
Autotrol 3/4" PVC Tube Adapters - Home And Garden Products - Amazon.com
Amazon.com: buffer tube adapter
Amazon.com: Legines Brass Tube Fitting, SAE 45 Degree Flare Adapter Union, 3/4" Flare Male to 1/4" NPT Male (2pcs) : Industrial & Scientific
Amazon.com: RuffStuff Specialties R1073 7/8 Inch Right Hand Threaded Standard HEX Tube Spherical Rod Heim Joint Adapter For 1 1/2 Inch ID Tube (14 TPI) : Industrial & Scientific
DLAB 18900024 DLAB Vt1.3.5,Tube Adapter, for 8 Holes Test Tubes, 20 mm Diameter, Used with Vt1.3/Vt1.2/Ps1.1, 10" Height, 1.89" Width, 10" Length: Amazon.com: Industrial & Scientific