The TEXAS INDUSTRIAL REMCOR PL.1181 1/8" COMPRESSION TUBING FITTING X 1/8" MPT gauge line fitting. The PL.1181 adapter is commonly used for
1/8 1/4 3/8 1/2 NPT Female To 1/8 1/4 3/8 1/2 Inch 3mm 6mm 8mm Tube Compression Union SUS316L Stainless Steel Pipe Fitting - AliExpress
Straight Fitting (1/4 COMPRESSION x 1/8 NPT) Full flow + SECURITY, these are the modern standard
90683 DOT Approved Male Connector, Compression Air Brake Fitting, Brass, 3/8 x 1/8
60438 KIT - VITON O-RING 3/4 SINGLE UNION BALL VALVE
1/8 COMPRESSION TUBING FITTING X 1/8 MPT
1/8OD X 1/8MPT Brass Compression X Male Pipe Thread Straight Connector — COPPERTUBINGSALES
1/8 F NPT straight compression fitting for 1/4 O.D. tube - Kleinn Automotive Accessories
1/8 PRESSURE GAUGE TUBING
PK-AB144-1-VI-KIT REPAIR KIT, VITON
683A - BRASS COMPRESSION COUPLING 3/16 OD X 1/8 MPT