Modifies the "Create New Level 30 Character" options in the save selection with a variety of options, including:
Level - Boost the character to 50, 72, or 80. (Will still display as "Level 30" in the menu.)
Black Market Upgrades - Start out with a decent portion (or all) of the upgrades in the Black Market.
Playthroughs - Complete the story missions for Normal Vault Hunter Mode, or both Normal Mode and True Vault Hunter Mode to unlock Ultimate Vault Hunter Mode.
Currencies - Set your starting values for Money, Eridium, Seraph Crystals, and Torgue Tokens.
Better Starting Gear - Replace the usual gear you'd get with your new character with a collection of gear more palpable than green items. Typically not the BEST gear for that character, but useful. You'll want to toggle this to match whatever level you chose for your character.

Concerning Overpower Levels:
OP Levels are a little different to handle; you'll need to execute a command in-game after you've picked your character and hopped in to "Fight for Sanctuary". The command in question is:
set WillowPlayerReplicationInfo NumOverpowerLevelsUnlocked 10

After you spawn into "Fight for Sanctuary", be sure to travel to another map so that your currencies and such save. Then you can exit and reselect the character to choose the playthrough.