Blue Gauge (low): 2-1/2" diameter, 0-120PSI with 0-40VAC,Yellow 6Ft charging hoses (1/4" ACME x 72" with knurled fittings)Red Gauge (high): 2-1/2" diameter, 0-500PSI,Red & Blue 6Ft charging hoses (1/4" FFL x 72" with knurled fittings)Burst pressure: 3000PSI, Max. working pressure: 600PSIAluminum body, Extra large sight glass,Each couplers have a shut off valve to prevent loss of refrigerantSet includes quick disconnect couplers for high/low side fittings