Steel band or Band chain. Steel band or Band chain consists of a long narrow strip of blue steel of uniform width of 12 to 16 mm and thickness of 0.3 to 0.6mm. Metric steel bands are available in lengths of 20 or 30 m.
To know more about the types of chains used in surveying, check the article link given below.
https://theconstructor.org/surveying/types-of-chains-surveying/13889/4