Original poster: "by way of Terry Fritz <teslalist@qwest.net>" <BA1ELECTRONICS@aol.com> HI ALL, EG&G INC PART # GP-30B. THEY CAN BE SEEN AT :WWW.PERKINELMER.COM DO SEARCH FOR SPARK GAP. THEN CLICK ON TRIGGERED SPARK GAPS. THEN CLICK ON DOWNLOADS:TRIGGERED SPARK GAP DATA SHEETS. I ALSO HAVE ONE ON E-BAY ITEM # 3310843597. CHEERS , BART AVERY