ABN AC A/C Refrigerant 500 PSI Brass Manifold Gauge Set with Couplers 500 PSI Brass Manifold Gauge Set with Couplers, Great for a DIYer Specifics lue (Low) Gauge: 0-120PSI, Blue hose: 1/2 inch FFL * 50 inch, Red (High) Gauge: 0-500PSI, Red Hose: 1/4 inch FFL * 50 inch, Yellow Hose: 1/2 inch ACME * 50 Inch.