I’m not a big fan of bamboo needles since the tips tend to get splitty and catch your yarn after a while. I MUCH prefer these silky smooth birch needles from Knitters Pride. 40″ is my go-to length for magic loop when knitting two socks at a time.I only carry the sock sizes in fixed length circular needles. If you need bigger needles, check out the selection of interchangeable needles instead.