CNC machined from a solid block of Pure Brass. Weight: 135g Powerful Japan motor- increased torque with less voltage. This machine could be used both shading, lining, large area coloring Stroke Length:2.5-4.2mm. Ergonomic, lightweight. Designed for use with standard and cartridge needles This rotary machine have spring and armature bar set-up that ensure more Stable frequency, have stronger rebound. Re-engineered and Special frame for a smoother, quieter operation at a lower voltage without stalling.Instruction:Lining: Stroke length 3mm, operating voltage 6V-7V for 3RL-9RL sizes grouping needlesStroke length 4mm, operating voltage 7V-8V for 11RL-18RL sizes grouping needlesShading: Stroke length 3mm, operating voltage 5V-6V for 5M-9M sizes grouping needlesStroke length 4mm, operating voltage 6V-7V for 11M-15M sizes grouping needlesStroke length 4.2mm, operating voltage 8V-9V for 15M- sizes grouping needlesSpecifications: Weight:135g Powerful japan motor-increased torque with less voltage Rotation :8V/9000rpm Stroke Length :2.5-4.5mm