GDZG-300 usoro nke DC high voltaji tester na-anwale DC elu voltaji maka zinc oxide ọkụ arrester, magnetik ịfụ arrester, ike cables, generators, transformers, switches, na ndị ọzọ na ngwá, nke kwesịrị ekwesị maka eletriki alaka alaka, ike ngalaba nke ụlọ mmepụta ihe, ngalaba nyocha sayensị, okporo ụzọ ụgbọ oloko, ụlọ ọrụ kemịkalụ, ụlọ ọrụ ọkụ.