Rolling Shutter Door Spring Box
Outer Diameter: 200/220/240 mm
Inner Diameter: 32/45/50/60 mm
Height: 70/80/93 mm
Thickness: 1.0 or 1.2 mm
Spring box material: Zinc Coated, not easy to break, long lasting
Ball bearing material: iron ball, nylon, bearing
Ball bearing: Low rolling resistance, Not easily attrited, smooth and flexible
Surface: smooth grinding
Application: Shops, Warehouses, Garages, Shopping malls etc.
