... two ends and diapgagm valve in the middle Description: Gauge Type:1.Pressure& temperature unit: PSI/Kpa ,oF/ ... oC; Refrig scales& gauge diameter: R134a, R-22, R-404a, R-407c, ... & temperature unit: PSI/Kpa ,oF/oC; Refrig scales& gauge diameter: R-410a, R-22, R-404a, 80mm/3 ... temperature unit:PSI/Kpa ,oF/oC; Refrig scales& gauge diameter: R12, R-22, R502, 80mm/3.5"