The Coiled rebars/spooled rebars are round steel bars with relatively small diameter. Common Grade of Spooled Rebar is HRB400 and HRB500. The product form is spooled rolled rebar for supply. The common ones are 10 mm, 13 mm, 16 mm and 19 mm in diameter. Drives are mostly low -carbon steel, generally not used for the main tendons of reinforced concrete structures, mostly used for reinforced steel sleeves, as well as small diameter for "brick-and-tendon" in brick -concrete structures.