These Low/High side retrofits/adapters/fittings will convert your old 3/16" or 1/4" R12 charging port and make it accept the R134a quick disconnect hose. Charging port adapter R12 Port to accept R134a 'Quick Disconnect'. Time-saving and effort-saving while installing, lightweight, shortcut. Can be matched used with valve by connecting with screw thread. There are valve inside, equipped with a plastic protective cap. Specification: Material: metal and plastic. Color: blue(low), red(high). Size: red:3/8'(high). Bule: 7/16'(low). Note: There might be a bit color distortions due to different resolutions. There might be size errors due to different resolutions. Package include: 1 * R12 to R-134A adapter set(show as pictures).