This LTWFITTING Compression tube fitting is made of brass for durable. And it connects to tubing on one end and has an NPT male connector on the
LTWFITTING 1/4 in. O.D. Comp x 3/8 in. MIP Brass Compression
LTWFITTING 1/4 in. O.D. x 1/8 in. MIP Brass Compression 90-Degree
LTWFITTING Brass 3/8-Inch OD x 1/4-Inch Male NPT Compression Connector Fitting(Pack of 5) : Industrial & Scientific
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LTWFITTING 5/8 in. O.D. Comp x 3/8 in. MIP Brass Compression
LTWFITTING Brass 5/8-Inch OD x 3/8-Inch Male NPT Compression Connector Fitting(Pack of 5) : Industrial & Scientific
LTWFITTING 1/8 in. OD Comp x 1/8 in. FIP Brass Compression Adapter
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LTWFITTING 1/8 in. OD Comp x 1/8 in. FIP Brass Compression Adapter Fitting (25-Pack) HF662225 - The Home Depot