Fullbottle Buster

The Ultimate Power Change Fullbottle Buster (究極豪成フルボトルバスター) is the personal weapon of Kamen Rider Build's RabbitRabbit and TankTank Forms.

Design
The FullBottle Buster consists of the following parts:
 * Crash Site Wrench (クラッシュサイトレンチ): An aiming sensor located on top of the blade. Not only is it used to help correct the user's aim during attack, but it can also be used to pinch, and possibly peel off the enemy's armor.
 * FB Buster Blade (FBバスターブレード): The slashing unit of the FullBottle Buster in Blade Mode. This is said to be able to cut through a Guardian Union, and has a chainsaw built into it for a boost in attack.
 * Full Blade Grip (フルブレイグリップ): The grip of the weapon, not only can it be used to optimize attacks by recording and analyzing the user's habits and the enemy's behavior, but it can also be used to hit nearby enemies with its hammer-like end.
 * Full Assist Grip (フルアシストグリップ): A secondary grip located at the back of the muzzle. It's job is also to suppress recoil during shooting attacks, and raising the hit rate.
 * Full Bottle Releaser (フルボトルリリーサー): A red button used to discharge and release fullbottles.
 * FB Buster Cannon (FBバスターキャノン): The bombardment unit of the FullBottle Buster in Cannon Mode. Not only can it emit a heavy light and energy grenade that can erase the target, but it can also be customized according to the situation by adjusting the fire resistance, explosive power, caliber, etc.
 * Quad Full Bottle Cylinder (クアッドフルボトルシリンダー): A long channel that can hold up to four FullBottles at the same time for special attacks. The contents of the bottles are taken into the weapon, and activates a deathblow with the strength depending on how many bottles are loaded.
 * Select Lancer (セレクトランサー): A hinge for switching between blade and cannon modes that can be rotated simply by holding a button.
 * Break Match Trigger (ブレイクマッチトリガー): The trigger of the weapon. When FullBottles are loaded, and the trigger is pulled, the deathblow will be initiated.

History
The Fullbottle Buster was designed by Sento along with the FullFull RabbitTank Bottle.

Modes
This weapon has two modes: the sword-like Buster Blade Mode (バスターブレードモード) and the pump-action shotgun-like Buster Cannon Mode (バスターキャノンモード).

Finishers
By inserting up to four Fullbottles into the weapon's Quad Full Bottle Cylinder, it can activate special finishing moves:

One Fullbottle=
 * Fullbottle Break (フルボトルブレイク): Activated by inserting a single Fullbottle into the Fullbottle Buster.
 * Buster Cannon Mode:
 * Rabbit: Build fires a ball of red energy at the enemy.
 * Magnet: Build fires a blast of blue energy that pulls enemies towards each other to the point where they explode.