The apparatus, in acc with ASTM D 113, D 5976 – IP 32 – ISO 1208 – EN 13398, 13589, 13703 consists of a constant temperature bath capable to work in the range from -10 to 40 °C (thanks to a built-in cooling compressor) with an electrically powered tractor that pulls apart at a determined speed the two ends of two briquet specimens: the elongation is measured by means of a pointer on the tractor and a graduated scale fixed to the cover.