Copper Nickel Plating Ferrule Compression Pipe Fitting Connector Thread 1/8 1/4 3/8 OD 4 6 8 10 12mm Tube Adapter PC PCF PL PB - AliExpress
LTWFITTING Assortment Kit Tube OD 3/8" 7/16" 1/2" 5/8" Brass Compression Union Set (25-Pack) HF62L4MIX - The Home Depot
Metalwork 304 Stainless Steel Metric Compression Tube Fitting, 12mm Tube OD x 1/2 NPT Male Adapter Connector Coupler (2 Pcs) : Industrial & Scientific
Instrumentation Tube Fittings, Instrumentation Ferrule Fittings, Instrumentation Compression Fittings, Tube Connectors
3/8 in. Tube O.D. x 1/4 in. Male AN - AN Union - Double Ferrule - 316 Stainless Steel Compression Tube Fitting