Interdynamics Certified A/C Pro R-134a Manifold Gauge & Hose Set, 429 CERTIFIFIED - Certified A/C Pro Automotive Air Conditioning R-134a Manifold Gauge & Hose Set is used to check both low and high side pressures while adding refrigerant. PROFESSIONAL GRADE - This professional grade kit features SAE approved 72 inch hoses (blue low-side, red high-side), and 60 inch yellow charging hose. CAN BE RECALIBRATED - The manifold has low and high pressure gauges that can be recalibrated. GUAGE & HOSE SET - Professional R-134a manifold gauge and hose set also comes in a blow molded plastic case. BUILT IN FEATURES - High and low pressure quick couplers with shutoff valves