Ibyuma bihanitse bidafite ibyuma byihuta ni uruziga rw'icyuma gifungura uruhande rumwe kandi bikozwe kuva 304 cyangwa 316 ibyuma byo mucyiciro.Iyo ihuriro rimaze kuba, uhita uhinduranya akaboko hejuru yugurura kugirango ukomeze. ikintu gikomeye nuko itazabora mugihe, ndetse no mubirere bitose.Nubwo bikunze kuza mubunini hagati ya 3.5mm na 14mm, niba hari ubunini bwihariye urimo gushaka noneho nyamuneka utubaze nkuko bishoboka cyane ko dushobora kubitanga.