The measurement of extra flexible tinned copper is ≤0.5². For extra-flexible plain copper falling under NFC 32013/IEC 228 Class 6, measurement is > 0.5². This is miniaturized, of special polymer for robotics. For cores stranded in twisted pairs and wound by an anti-friction tape, spun by tinned copper , the optical coverage is 95% compared to 85% for tinned copper braid with stranded pairs wound by anti-friction tape. The polyurethane mat has very good mechanical properties