Beduan 304 Stainless Steel Air Compression Tube Fitting, 6mm Tube OD x 6mm Tube OD, Equal Straight Connect for Tubing Pipe Line (Pack of 2): Amazon.com: Industrial & Scientific
6mm x 1/4'' NPT Push-in Fitting with Male Threads Stainless Steel FKM | Tameson.com
6mm x G1/4'' Plug-in Fitting with Male Threads POM EPDM [5 Pieces] | Tameson.com
Amazon.com: 6mm Push to Connect 1/8 Inch NPT Air Fittings Push in Connectors Air Line Quick Connect Fittings,CEKER 6mm OD Tube Fittings Pneumatic Fittings Air Hose Fittings 3D Printer Accessories 10Packs :
6mm x 1/4'' NPT 90deg Elbow Push-in Fitting with Male Threads Stainless Steel FKM Rotatable | Tameson.com