Unique spring pressure indicator, the accuracy error is 1.5 grades. Check the low pressure side pressure to accurately charge the air conditioner R134A refrigerant. Blue Gauge (Low): 0-220 PSI; Red Gauge (High): 0-500 PSI Celsius unit, large instrument panel, easy to read instrument panel, easy to see during use, and sturdy construction. Equipped with high and low disconnect couplers High pressure hose with 1/4" SAE male flare and three 60" (5 ft) lengths of color coded service hose. Complete diagnostic and service instrument cluster for air conditioning systems. Ideal for R134a systems Made of solid bass + aluminum + PVC + plastic, it can withstand heavy use and accidental drops, ideal for professional auto mechanics. Includes detailed parts diagrams and step-by-step instructions to assist novices PACKAGE INCLUDES: Colorful trio of 60" hoses, manifold gauges, accessories, and storage bag to keep equipment clean and dust-free