timpani (kettle drums)
Non transposing instrument.
Concert pitch is an octave lower than written.
Scored in bass clef. The parts are extracted to bass clef.

There are 4 timpani. Only two may be available. The most common are the 23" and 28". The lower timpani is tuned to the root of the chord, the higher timpani to the 5th. Rework your chords so a passage can be played without re-tuning. It takes plenty of time to re-tune a timpani.

Overuse of the timpani lessons the impact of the arrangement.