Loop length is the length of yarn used for a single stitch, usually measured in millimetres. It is set on the machine and determines how tight or loose the knit is. A long loop gives a looser, softer, stretchier and lighter fabric, but with more shrinkage. A short loop gives a denser and more stable fabric.
That is why two fabrics from the same yarn can have different weights and behaviour. For repeat lots, ask for the loop length to be kept constant, so that there are no differences in weight, width and shrinkage between batches.
loop lengthstitch length
