2x Stainless Steel 304 Compression Tube Fitting Adapter 3/8″ OD x 3/8″ NPT C582
Notice: “OD” is the size of the tube you will connect, not the size of the female compression. NPT is the size of the male thread, not the OD of the male thread. Compression fitting just can be used for connecting hard tube, such as steel tube, copper tube, etc.