Calibrators quickly field-check accuracy of pressure- type concrete air meters. With canister in the water-filled base, air meter gauge should read 5% air in a simulated test. Two calibrators are used in a 0.25ft³ meter for a 10% air reading. In 0.5ft³ meters, percents are halved; 2.5% for one, 5% for two, 7.5% for three canisters, etc.
HM-24 Calibrator is of precisely machined brass. 7.5x2.125in (191x54mm), height x diameter with 0.5in (13mm) thick stabilizing base. Est. Ship Wt.: 3lb (1kg).
HM-25 Economy Calibrator is rugged plastic with metal weighted ring. 3.75x4in (95x102mm), height x diameter. Est. Ship Wt.: 3lb (1kg).
HM-27 Lightweight Aluminum Calibrator is accurately machined to exact dimensions. They are sturdier than plastic, less expensive than brass models. 5.63x3.25in (143x83mm) height x diameter.