You need one set of needles to reach the the gauge size (see sizes below), and one set which are 0.5mm below the gauge size.
For the Medium Women’s size, we recommend swatching with 3mm needles to achieve a 32st/10cm gauge.
Your needles should be suitable for small circumference knitting – either DPNs, Asymmetric Circulars, 80cm circulars for magic loop or Addi Crasy Trios.
Different mitten sizes are made by adjusting your stitch gauge with different sized needles.
The following gauges create the following sizes
34 sts per 10cm/4” for pre-teen, 9cm width.
33 sts per 10cm/4” for teen/women’s small, 9.5cm width.
32 sts per 10cm/4” for women’s medium, 10cm width.
31 sts per 10cm/4” for women’s large/men’s small, 10.5cm width.
29 sts per 10cm/4” for men’s medium, 11cm width.
28 sts per 10cm/4” for men’s large, 12cm width.
For reference, Eli used 3mm to get the right gauge for a medium women’s size.