High-pot tester transformer, 115vac primary, 15kV, 30mA secondary, Jefferson Elec., potted, glazed porcelain insulators, current-limiting type/short-proof. Using variac in pri. - with FWD, 0V-42kVDC or 21kVDC with half-wave. A useful tool for building and servicing tube-type amplifiers. Ship UPS. Best offer. - Rich..., 805.386.3734, www.vcnet.com/measures.