Twin Boy and Girl Shirts, Includes 2 Tshirts, Womb Mates, Twin 1 Twin 2 Amazon size chart is not specific to our brand. Please see Description for dimensions on t-shirts Screen printed design on Cotton tshirts for comfort and softness. Gift Set Includes 2 t-shirts Heather Gray shirts are 65/35% cotton-poly blend. The graphic design is a registered copyrighted design. Infringing companies will be prosecuted.