4 pieces Brass 5/16 Line Compression Fitting Union Steel Copper

( 4 ) Brass Compression Fitting Union 5/16" OD Tubing. Will work on Steel, Copper, Nylon, Plastic, & Copper/Nickel Lines.

Compression Tube Fittings - RFS Hydraulics

5pcs Brass Brake Line Union Fittings Straight Reducer Compression Kits Connector 3/16 Od Hydraulic Brake Lines Pipe 33 X 10mm - Nuts & Bolts - AliExpress

Brass Straight Reducer Compression Fittings Connectors Fit 3/16 Tube Od Brake Lines Union Adapters 229 Psi - Pipe Fittings - AliExpress

LASCO 17-6219 5/16-Inch Compression by 1/4-Inch Compression Brass Union : Everything Else

Fuel Line Compression Fitting 5/16 Line to 1/8 Pipe - DJS Tractor Parts

5/16 in End B Diameter Compression Fittings

Stainless Steel Reducing Tube Unions - 3/8 x 5/16 Double Ferrule LOK

5/16-in x 1/4-in Compression Reducing Union Fitting

Proline Series 5/16-in x 1/4-in Compression Reducing Union Fitting

S.U.R. & R K060 3/8 Nylon To Steel Compression Fitting (2)