Double-ended one pin UV germicidal lanps Quick start, save ... ZW40S25Y-Z1199 stands for:UV germicidal lamp ,150W, double-ended, OD 25mm, ozone produce, ozone free, tube length ... H164 stands for:UV germicidal lamp,13W,single-ended,OD 12mm,ozone produceW,ozone freeZ,tube ... germicidal lamp,150W,double-endedS,OD 15MM,ozone produceYozone freeW,tube length is 1554MM Double-ended one pin UV germicidal lamps