Byuzuye-byuzuye bya silindrike ya roller igizwe nimpeta zikomeye zo hanze ninyuma hamwe nizunguruka ziyobowe na rubavu.Kubera ko ibyo biti byerekana umubare munini ushoboka wibintu bizunguruka, bifite ubushobozi buke bwo gutwara imizigo ya radiyo, gutwara cyane kandi birakwiriye kubishushanyo mbonera.
