Square 110 is 110 x 110 cm and the size most of these prints were drawn for. It ties short, folds to a triangle that sits at the shoulder, and is the one to take if you are buying a first.
Square XL 135 is 135 x 135 cm. The extra twenty-five centimetres is what lets a square be worn loose and long without the point riding up, and it carries a large repeat better because more of the drawing stays visible once it is folded.
Long Shawl is 175 x 70 cm, cut for wrapping rather than folding, and it is the shape to choose if you want the print to run rather than repeat.
Instant M and Instant L are cut and sewn to shape rather than squares, so there is nothing to tie. Measure around the head above the ears: up to 55 cm takes M, above that takes L.