Previously we have reported the design and construction of two CSIRO Fineness and Maturity Testers (CSIRO FMT). A third instrument has been constructed and all three instruments have been modified to incorporate an additional absolute pressure sensor which is used to compensate for variations in external pressure leading to improved consistency of measurement. All three instruments have been calibrated to the Head Space Resistance Standard (HSR). The results from an international inter-laboratory trial which has tested a range of cottons are reported.