Down Stem bụ iko sayensị nke jikọtara ọkpọkọ mmiri nke ụdị tube na efere slide ya.Ọ dị mfe ịgbaji ma nwee ike iru unyi ka ndị mmadụ nwee mmasị ịnwe nhọrọ nnọchi.
Oghere a dị ala nwere ihe dabara adaba nke nwoke 14mm na nwanyị dabara adaba 14mm.Emere ya ka ọ dabara na ọkpọkọ mmiri nwere oghere 14mm.
Ọ na-eduga na nwanyị dabara adaba na oghere 14mm.Ihe ngwakọta a tinyekwara nnukwu efere mmịfe nwoke 14mm.
Ugbu a ihe niile ịchọrọ bụ ọkpọkọ mmiri nke nwere oghere 14mm.