Awọn ẹrọ fifọ rọba joko laarin ohun-irọra ati oju rẹ lati rii daju pinpin iwuwo paapaa ati daabobo dada lati gbigbọn ati ija.Bó tilẹ jẹ pé washers le yato ni sisanra, apẹrẹ, ati iwuwo, won ojo melo ya awọn fọọmu ti ri to roba oruka pẹlu kan aringbungbun iho fun awọn fastener.
