How many letters does the top answer for “a pen that has a small metal ball as the point of transfer of ink to paper” have?

The most common answer is ballpoint (9 letters).

Crossword clue: a pen that has a small metal ball as the point of transfer of ink to paper

2 answers found in Letterora's clue database (Wikidata facts, Open Trivia DB, WordNet and Webster definitions — all licensed sources).

ballpoint 9 letters wn-def

a pen that has a small metal ball as the point of transfer of ink to paper

biro 4 letters wn-def

a pen that has a small metal ball as the point of transfer of ink to paper