WIKA's robust and modular calibration systems are designed for checking the SF6 gas density and pressure measuring instruments. The test item is connected to the calibration system via an adapter and, by automatic pressure generation with a hand pump, makes it possible to exactly approach the measuring points. A subsequent comparison of the displayed values or switch points of the test item and reference instrument allows assessing the instrument's suitability for on-site use. The instrument is always protected and ready for use with the robust service case and additional foam inserts.