Delicate yet strong flat steel corset boning for where a lot of boning without a lot of weight is required, ie: in fully boned corsets where there is a bone at every point along the waistline.  This size corset boning, with the exception of the plastic coating, is very much like the boning I have seen in antique Victorian corsetry.  Also suitable for stays.

Narrow but heavy guage steel where 'delicate' yet very strong support is required.  Aesthetically, this would combine very well with 4.5mm flat boning in a fully boned corset.   Most suitable for boning your corset at places where little flex is required, ie: back panels.  This boning is very suitable for centre back panels too, despite it's narrow width.

Standard guage and suitable for corsetry and dress making,  this steel is very easy to use and easy to cut.  Suitable for all applications in corsetry, costume and modern day dress making can be used in corsets, bodices, petticoats, bustles, paniers and crinolines.

Nice width of steel can be used in side seams as per certain Victorian corsetry examples i've seen where more support is required in that area, or back panels.  Good for 'plus size' corsetry and centre back panels.  As above, this steel is also used for making cage petticoats, paniers and related steam punk outifits and costumes.