Chiaogoo's fixed Bamboo Circulars are made of Moso bamboo which is the largest and strongest bamboo out of over 1,000 species. These circulars are nickel-plated, copper join that is glued and crimped to guarantee no separation. The joins are fantastic, the nylon cable is pliable and the tips swivel freely! Needle size is permanently laser imprinted on each circular. Product image shown covers a range of needle sizes.