Our TWIST™ Short Combo packs contain one 2″ (5 cm) and one 3″ (8 cm) set of the same size tip as well as two cables allowing knitters to make 9″ (23 cm) – 12″ (31 cm) circulars. Sizes 000 (1.5mm) – 3 (3.25mm) have a MINI [M] size join. Sizes 4 (3.5mm) – 8 (5mm) have a SMALL [S] size join. All tips are solid and have a tightening hole EXCEPT for the 3″ (8cm) US4 (3.5mm) – US8 (5mm) which are hollow.