I-crustrivers yesandla zilungele ukutywina kwe-Alumuminium ye-Alumnum ye-SAPS yobukhulu obahlukeneyo kwaye ziyafumaneka njengoko kulungelelaniswa. I-crustr ehlengahlengisiweyo ibonelela ngendawo eguqukayo kwisibambo ukuqinisekisa ukuqinisa nokukhululwa kwecakethi ngalo lonke ixesha, kwaye ubunzulu bobuchule bunokutshintshwa ngokuhlengahlengisa izikrelem kwi-screpp.