1, na'ura mai auna firikwensin elastomer ne ginshike-irin, silinda-irin, ginshike-irin zobe-irin tsari, don auna karfin jan hankali da matsawa.
2, cikakken hatimi tsari, m range, aiki da kwanciyar hankali da amintacce, shigarwa da sauki amfani.
3, jawo matsa lamba irin daukar.
4, dace da daban-daban m / weighing masana'antu sarrafa kansa ma'auni iko tsarin.