this one you can also use ,,,,,,but its little complex to use ,,,,, as you have to play with lot of unit conversions,,,,,, a much simpler and yet accurate is known as krikit tension gauge ,,,,,, i am sure it will be also available on aliexpress or amazon ,,,,, the one shown in workshop manual has similar working principal to the one you have shown ,,,,but may be an older version,,,,,,,,,