Lightweight aluminum rims without eyelets often have burrs on the nipple seat. These increase the workload of Spoking immensely because the ridge has to be leveled by the nipples and the friction increases. For a better fit of the nipple into the rim it Rec kept, the spoke holes to reduce previously with a deburrer something.
Material: aluminum, steel
Note: Color of the handle may vary depending on your mood of tune ;-)