VDF-based curable fluorelastomers, having a glass transition temperature from −10° C. to −35° C., comprising: B) monomer of formula: CF2═CFOCF2OCF3 (a), C) one or more comonomers selected from: tetrafluoroethylene (TFE), per-fluoromethylvinylether (PMVE), perfluoropropene (HFP), and an amount of —COF end groups in the polymer lower than the sensitivity limit of the method which uses the FT-IR spectroscopy described in the present application.