Oring, flare, quick disconnect and metric are four of the main a/c connections. Coldhose uses pictures to identify these fittings. Please match your fitting to the picture as a quick reference when choosing what part you need. The fittings listed on the site have the hose and thread size also. Please be sure to choose the correct size for your application. All of the fittings listed use standard (barrier) air conditioning hose and beadlock fittings. If you have the barb style fittings with hose clamps it is recommended they are replaced with beadlock fittings. Some flare fittings are barb style with crimp sleeves (ferrules) included. The ferrule will work with R-134a crimp tools.