A line of medical-grade power transformers has been expanded up to 6,000 VA. The line is certified to the most recent revision of UL60601-1, the Canadian CSA std c22.2 No. 601.1, the European standard EN 61558-1, and the International IEC60101-1. The amendments of both EN and IEC are the most recent available. The certification includes isolation and step-down transformers with primary and secondary voltages up to 240 V and operating frequencies of both 50 and 60 Hz. The price of a 1,000 VA transformer certified to the medical standards in lots of 100 pieces starts at $98, depending on available options such as a static shield between primary and secondary windings, auto-resettable fuse, low leakage current, non-standard ratio of diameter to height. These transformers use a round toroidal core construction, which makes the transformer a Class II design as no live parts of the transformer carrying current are exposed. Other advantages of the toroidal core construction over the conventional stacked lamination type includes size and weight reduction of up to 50 percent, higher efficiency, quiet operation, low no-load losses, and cooler operating temperature. The low weight and the low profile of the toroidal transformer, typically with a diameter to height ratio of 2 to 1, makes it suitable for contemporary designs of medical devices.