Question about "Skills fire an additional Projectile"

I was wondering if this works on traps like "fire trap". Would it throw 2 traps instead of 1, with a single cast with this gem skill?

thanks

No. Look at gem tags next time.

Typically with added projectiles, it will only affect skills with a "projectile" tag, and then will only further affect the PROJECTILES of the skill.

Take "Lightning Trap" as a better example: The extra projectiles would affect the total number of projectiles fired by the trap, but not the amount of traps as they are not projectiles.