Bitspower G1/4" to 3/8" ID, 5/8" OD Compression Fitting V3 for Soft Tubing, Matte Black, 4-Pack For Tubing with 3/8" ID (Inner Diameter) and 5/8" OD (Outer Diameter) G1/4" thread Hi-Quality Brass Material Hidden O-ring Design Color: Matte Black