swivel caster,heavy duty caster 1.caster wheel without braker system, 2.heavy duty,apply ... zinc,nickel free,enviremental friendly;the wheel is light blue.3.specifications:wheel sizes:4inch,max burden:60KG/piece ... ,wear-resistant,silence wheel.If you want to more details,please contact ... large flight case,duo to the heavy duty elastic rubber wheel,it can run in silence.It has a ...