1. Ibyuma bitagira umwanda bifite ibiranga plastike nini, ubukana bwinshi, nimbaraga nyinshi zumuriro, kandi bifite imyumvire ikomeye yo gukora gukomera, bisaba ubuziranenge bwibiti bya bande.2. Icyuma kibonye kigomba kugira ubushyuhe bwiza no kwihanganira kwambara. Bimetallic isanzwe isanzwe ibona ibyuma bikoreshwa mukubona ibyuma bya karubone ntibikwiye gutunganywa