Soft and breathable material. A slim fit. 100% cotton t-shirt. 

measurements:
6 month length 35.5cm, body width 28cm, arm hole 8.5cm neck width 13.5cm
12 month length 37cm, body width 29.5cm, arm hole 9cm neck width 13.5cm
18 month length 38.5cm, body width 31cm, arm hole 9.5cm neck width 14cm
2 years length 40cm, body width 32.5cm, arm hole 10cm neck width 14.5cm
3 years length 42cm, body width 34cm, arm hole 11cm neck width 15.5cm
4 years length 44cm, body width 36cm, arm hole 12cm neck width 16.5cm
5 years length 46cm, body width 38cm, arm hole 13cm neck width 17.5cm
6 years length 48cm, body width 40cm, arm hole 14cm neck width 18.5cm