1. Stack material higher grade / lower temperature rise/ high performance. 2. Commutator copper grad higher and small bar to bar surge lead to lower spark and higher endurance. 3. Copper wire grade 2 endurance for high temperature. 4. Epoxy resin to protect the copper wire from moving to avoid burning for big vibrarion hammer. 5. Shaft mater better on hardness and gear. GBH5-40 rotor suitablefor GBH5-40D GBH5-40DE GBH5-40DCE GSH5E GSH5CE 1619P10769 220-240V Different batches may have slight color differences or differences in the actual product, which not affect the use Notice: The blades color is random, cannot be chosen the specified color. Colour:As Shown Material:Metal Package Contents: 1 x Armature Rotor Anchor Replacement Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.