Dress your little one in these baby trousers, knitted in PHIL PARTNER 3.5, ensuring warmth and softness. To make this design, you will need: Needles size 3.5 for stockinette - Needles size 3 for 1/1 ribbing. This intermediate level pattern is explained in the following sizes: Newborn, 3 months, 6 months, 12 months, and 18 months.