Calibrators quickly field-check accuracy of pressure-type concrete air meters. With a calibrator in the water-filled base, air meter gauge should read 5% air. Two calibrators are used in a 0.25ft? meter for a 10% air reading.

HM-24 Brass Calibrator is of precisely machined brass. 7.5x2.125in (191x54mm), HxDia. with 0.5in (13mm) thick base. Est. Ship Wt.: 3lb (1kg).