The 3" (8 cm) precisely-machined, lace tips are made of surgical stainless steel. Sizes US000 (1.5mm) – US3 (3.25mm) are solid, have a tightening hole and MINI [M] diameter join. They need MINI cords.These are included in the Red Shorties set. Sizes US4 (3.5mm) – US8 (5mm) are hollow and have a SMALL [S] diameter join.These are included in the Blue Shorties set. They need SMALL cords. Sizes US9 (5.5mm) – US11 (8mm) are hollow and have a LARGE [L] diameter join. These are included in the Yellow Shorties set. They need LARGE cords. The size is laser imprinted on each tip. MADE IN CHINA