choice of different insulation builds (with different insulation thickness), allows optimization of products like smaller transformers, and gives a cost advantage
high temperature class of FIW acc. IEC 60172 of 180 °C
thermal life time acc. UL 2353 Annex U was approved for transformers with temperature class B (130 °C) and class F (155 °C) for wire diameters of 0.10 - 0.71 mm as well as for reinforced class 155 °C for wire diameters of 0.10 - 0.50 mm.
proven insulation system acc. UL 1446 of enamelled wires also with UL, used over many years