The first two (baby) sizes have a buttoned opening at the shoulder, the toddler sizes do not.

Measurements
To fit age 0-6 months, 6-12 months, 1-2 years, 2-3 years
To fit chest 41, 46, 51, 56 cm (16, 18, 20, 22 in)
Actual size 46, 53, 56, 54 cm (18, 21, 22, 25 in)
Finished length 23, 27, 31, 35 cm (9, 10½, 12, 14 in)
Sleeve length to underarm 13, 16, 20, 26 cm (5, 6½, 8, 10 in)

Materials
Patons Fairytale DK
2, 3, 3, 4 X 50 gram balls
3, 3, 0, 0 buttons.