NYLON - Great for standard applications and offer wear resistance to keep the gear mesh tight for years.
KARBONITE -
4 times stronger than Nylon and offers even better wear resistance and super quiet operation.
METAL - For rugged applications and is
16 times stronger than Nylon but will wear much faster.
TITANIUM - Awesome, $$$ and for critical applications. Virtually no wears after years of use and 48 times stronger than Nylon gears.