Add simplicity to your air meter calibration with the Exact-Air™ calibration canister. Canister is simply placed directly into a .25 cubic foot air meter displacing exactly a 5% volume of air. Eliminates the need for removing a 5% volume of water during the calibration procedure. Use two canisters for 10% volume of air calibration. Meets or exceed ASTM C-231. AASHTO T-152.