Zero Gear

Zero Gear (5) (ゼロギア⑤) is a gear that when equipped turns that corresponding person's weapon into there signature weapon and in Roxas' case, the Kingdom Key+. It's 4 spaces wide, 1 row with an extra square and has room for 4 support pieces.

Trivia

 * If this Gear is equipped with one Ability Unit, the Keyblade will turn into Oathkeeper. If it's equipped with two, it'll turn into Two Across. If it's equipped with three, you'll turn into Dual-Wielding Roxas with both Oathkeeper and Oblivion which is only accessible during Mission Mode.