DIN Connectors are compact and have spring-loaded free-floating zirconia ferrules for superior performance. In addition to basic testing, some mechanical and environmental tests per IEC or Telcordia are also performed periodically to guarantee the best quality. For standard patch cords, sampling check is performed on ferrule geometry to ensure high percentage of polished connectors meeting GR-326 requirements. For premium grade, ferrule geometry is tested on all patch cords to meet these GR-326 requirements