Through merger and acquisitions, the company became a significant, but never dominating supplier of electrical distribution equipment, including transformers and switchgear, residential and commercial load centers and breakers, pushbuttons, indicator lights, and other hard-wired devices. All were manufactured and distributed under the brand name GTE Sylvania, with the name Challenger used for its light commercial and residential product lines. GTE Sylvania contributed to the technological advancement of electrical distribution products in the late 1970s with several interesting product features. At the time, they were the leading supplier of vacuum cast coil transformers, manufactured in their Hampton, Virginia plant. Their transformers featured aluminum primary winding and were cast using relatively inexpensive molds, allowing them to produce cast coil transformers in a variety of KVA capacities, primary and secondary voltages and physical coil sizes, including low profile coils for mining and other specialty applications. They also developed the first medium voltage 3 phase panel that could survive a dead short across two phases. Their patented design used bus bar encapsulated in a thin coating of epoxy and then bolted together across all three phases, using special non-conductive fittings.