S for tunnel widths from 9.5 - 16 mm
M for tunnel widths from 19 - 25 mm
L for tunnel widths from 25 mm
For turning tubes of fabric such as straps, belt loops etc. for turning tubes of fabric such as straps, belt loops etc.
Simple to use. Slide the outer blue tube inside your fabric tube then use the wood dowel to tuck the end of the fabric tube inside the end of the blue tube. Keep pushing the fabric tube into the blue tube until it is completely turned inside-out. Pull out of the opposite end of the blue tube and voila, the seam will be on the inside!