Automotive HVAC AC R134A System Hi/Low Quick Coupler Adapter For Manifold Gauges Blue: Low Side Quick Connector/Adapter (1/4 Inches SAE Male Flare) Red: High Side Quick Connector/Adapter (1/4 Inches SAE Male Flare) Coupler interface fits with R134 service ports,1/4" male flare 2 color coded straight quick connectors included Suitable for home or business applications