Zippers in 17 cm in a variety of colors can be found here

begin by knitting a swatch to determine which needle size will give you the correct gauge

Gauge: 21 sts x 28 rows = 10 x 10 cm [4 x 4 inches] in stockinette stitch on 4 mm [US6] needles with one strand of each yarn held together

Thin elastic thread for the neckband

Zipper Sweater Junior LANGUAGE:Dansk Zippers in 17 cm inThe Zipper Sweater Junior is worked from the top down. The collar is worked in rib, then folded double and knitted together. The yoke is worked with raglan increases, first back and forth on circular needles to create the slit for the zipper, then in the round on the circular needles. The body and the sleeves are worked in the round. Finally, a facing for the zipper is worked from resting stitches, so the zipper, after being sewn in, also looks