David, >From Victoreen 1997 catalog: SGCA- D.C. firing voltage: 1kV - 12 kV Tol: +/- 10% for all max energy/pulse: 100 J for all SGCB- D.C. firing voltage 12kV - 20kV SGCC- D.C. firing voltage 20kV - 35kV Victoreen is also an excellent source for kV-range resistors no prices listed in the catalog 6000 Cochran Road Cleveland 44139 tel) 440 248 9300 fax) 440 248 9301 www.victoreen-dot-com Ralph Zekelman