Item Boost

Item Boost (アイテムアップ) is an ability introduced in Kingdom Hearts II. It increases the effectiveness of recovery items. It can be multi-installed to increase its effects.

Mechanics
In Kingdom Hearts II, Item Boost is a that costs 2  to equip. Item Boosts on one character will not increase the effectiveness of items used by other characters. However, Item Boosts on one character will increase the effectiveness of items used on other characters. Item Boosts also do not affect items used from the menu; only items used in the field will be affected. Items boosts multiply the effectiveness of items by (0.5X+1). In other words, a potion (which restores 40% of the target's health) used by a character with two Item Boosts equipped will restore 80% to their target.

In Kingdom Hearts Birth by Sleep, Item Boost is a that can be installed up to three times.

In Kingdom Hearts 3D: Dream Drop Distance, Item Boost is a that can be installed up to three times.

In Kingdom Hearts III, Item Boost is a. It increases the effectiveness of restorative items used in battle by 50% for each ability equipped.

Kingdom Hearts II

 * Dual-Wielding Roxas has Item Boost as a default ability.
 * Sora learns Item Boost at levels 7 with the Dream Shield, 9 with the Dream Rod, and 17 with the Dream Sword.
 * Goofy has Item Boost as a default ability.
 * Mulan has Item Boost as a default ability.
 * Beast has Item Boost as a default ability.
 * Jack Sparrow has Item Boost as a default ability.
 * Aladdin has Item Boost as a default ability.
 * Tron has Item Boost as a default ability.
 * Riku has Item Boost as a default ability.
 * The Monochrome has Item Boost as its equipment ability.
 * The Rising Dragon has Item Boost as its equipment ability.
 * The Save the King has Item Boost as its equipment ability.

Kingdom Hearts II Final Mix

 * Dual-Wielding Roxas has Item Boost as a default ability.
 * Sora learns Item Boost at level 7 with the Dream Shield, 9 with the Dream Rod, and 17 with the Dream Sword.
 * Goofy has Item Boost as a default ability.
 * Mulan has Item Boost as a default ability.
 * Beast has Item Boost as a default ability.
 * Jack Sparrow has Item Boost as a default ability.
 * Aladdin has Item Boost as a default ability.
 * Tron has Item Boost as a default ability.
 * Riku has Item Boost as a default ability.
 * The Monochrome has Item Boost as its equipment ability.
 * The Nobody Lance has Item Boost as its equipment ability.
 * The Save the King has Item Boost as its equipment ability.

Kingdom Hearts Birth by Sleep

 * Item Boost can be attached to a, , , , , or Command recipe through Command Melding, either randomly or by applying a Soothing Crystal.

Kingdom Hearts 3D: Dream Drop Distance

 * Sora and Riku can purchase Item Boost from the Chef Kyroo Ability Link for 30, 50, and 100 Link Points.
 * Sora and Riku can purchase Item Boost from the Drak Quack Ability Link for 15, 25, and 50 Link Points.
 * Sora and Riku can purchase Item Boost from the Ducky Goose Ability Link for 15, 25, and 50 Link Points.
 * Sora and Riku can purchase Item Boost from the Escarglow Ability Link for 30 and 50 Link Points.
 * Sora and Riku can purchase Item Boost from the Juggle Pup Ability Link for 30 and 50 Link Points.
 * Sora and Riku can purchase Item Boost from the Kooma Panda Ability Link for 30 and 50 Link Points.
 * Sora and Riku can purchase Item Boost from the Ursa Circus Ability Link for 30 and 50 Link Points.
 * Sora and Riku can purchase Item Boost from the Drill Sye Ability Link for 30 Link Points.
 * Sora and Riku can purchase Item Boost from the Meow Wow Ability Link for 30 Link Points.
 * Sora and Riku can purchase Item Boost from the Pricklemane Ability Link for 30 Link Points.

Kingdom Hearts III

 * Baymax has Item Boost as a default ability.
 * The Warhammer+ has Item Boost as its equipment ability.
 * The Hero's Glove has Item Boost as its equipment ability.
 * The Star Medal has Item Boost as its equipment ability.