The NEW Silvera machine has a maximum speed of 14,500 rpm and is reduced by 1,500 rpm on each level. there are a total of 4 levels for this machine. The Machine has an adjustable Sleeve which is indicated by numbers around the ridge that will show the needle length setting. By twisting the sleeve it will adjust the needle length. Securely twist on the Needle Cartridge, but do not over tighten during assembly. By default the needle length is set at a maximum 3 mm of length and shortens as the indicated number reduces. The Needle Cartridge on this machine is mechanically designed to prevent cross contamination via a hidden needle for safe use and disposal. The cartridge hole allows for adequate airflow to prevent pigment buildup and backflow.