Black spoke nipples are available the "prolock" version. Prolock nipples contain a special locking compound which sets into place once the wheel is built and prevents the spoke from loosening. The wheel can still be trued if necessary. Prolock are not recommended for use with Revolution spokes as the spokes tend to twist when truing them due to the locking compound, thicker spokes can resist this.
All are 12mm length, and come in a box of 100