Strips of leather
We envisage bookbinders and bookcraft people using narrow strips of leather, instead of tapes, when sewing sections with open-back bindings (examples).
Wide, short, lengths are useful for the hinge when making longstitch bindings.
Wide, and long, pieces can be used for complete wrap-around soft covers. For these we envisage the width of the strip to be appropriate to the height of your book, plus an allowance for trimming.
For these uses, and any others you can think of, we sell strips of leather, which we make by cutting to the full width, or length, of a hide. We will then cut your required length from the necessary strip.
All our listed measurements are increased by approximately ten mm, or 1cm. This is to allow for cutting errors and bends or stretch of the leather. We could cut "exactly" but our version of "exact" may not be as accurate as yours. Also we are keen not to supply short measure. the ends of the strips are not squared-off, but our measurements are taken from the shortest point.
We use a wide variety of suitable leathers. It is unlikely that future orders will match current choices since we use a wide variety of different leathers and our suppliers stock changes much of the time. Should you require future consistency then we would advise buying a whole skin and cutting it yourself. There are numerous suppliers on the www offering various grades of leather, and probably hold matching stock to fulfil future orders.