Class E2 weights are supposed for use inside the initial verification of class F1 weights and for use with weighing devices of accuracy class I. Class E2 weights or body weight sets shall constantly be accompanied by a calibration certificate. METTLER TOLEDO's earth-leading know-how in metrology extends to check weights, https://horizontal-balers78900.timeblog.net/66987397/the-smart-trick-of-bailing-wire-that-nobody-is-discussing