You have practiced extensively with a variety of weapons both conventional and not, gaining the following benefits.

Increase your Strength or Dexterity score by 1, to a maximum of 20.

You gain proficiency with four weapons (including improvised and unarmed) of your choice.

When you roll damage with a weapon you are proficient with and do not roll the maximum on any of the weapons dice, increase the result by 1. 

When you critically hit with a weapon you are proficient with, you double any damage modifier as well.