Fullbottles

Fullbottles (フルボトル) are the sample bottle-like collectible devices used by the transformation gear in Kamen Rider Build.

Overview
The Fullbottles were created by Takumi Katsuragi as part of Project Build. They contain purified Nebula Gas to allow a person with a Hazard Level of 3 or higher to transform into a powerful armored form with the Build Driver or Transteam Gun. At some point 20 of the bottles ended in Hokuto and other 20 in Seito. Soichi Isurugi (Blood Stalk) faked the robbery of the Driver and serveral Fullbottles as part to make believe a girl named Misora (who was in charge of the purification process) that her job would be for a good cause. In order to make his plan work, Soichi erased the memories and faked the death of Katsuragi who wanted to quit the project after he had a change of heart. Soichi also gave the Driver and the Fullbottles to an amnesic Katsuragi now bearing a new face and under the name Sento Kiryu, making him believe that he was a Hero, while in reality he was unwittingly helping Soichi further his evil schemes.

Ten unique pairs of purified and Best-Matched Fullbottles from Touto exist, corresponding to Build's ten main forms. They are integral in Soichi's scheme, as he intended to use them to unlock the Pandora Box and access its powers.

After Build defeats a Smash, an Empty Bottle (エンプティボトル) is used to absorb the Nebula Gas from the victim, causing the Bottle to swell and gain a black spiderweb pattern and a Transgel Solid inside (often colored after the Smash, not the Fullbottle it will become), becoming the Smash Bottle (スマッシュボトル). Through a mysterious power held by Misora Isurugi, her gold bracelet, and a modified microwave machine in nascita's basement made by Sento, the harmful properties are purified, leading to the creation of a Fullbottle which can then be used by Build. Sento's machine isn't needed for the process, but reduces the bout of exhaustion Misora suffers following it from a full week unconscious to only a few hours of tiredness.

Before undergoing the purification process, the contents of Smash Bottle can be poured back upon the victim, transforming them back into a Smash. However, if one had their previous Smash Essence extracted, and they use a new Smash Bottle, they will disintegrate and die.

Functionality
Kamen Rider Build transforms by inserting two Fullbottles into the Build Driver and turning the lever. Organic-type Fullbottles (有機物系のフルボトル) are inserted into the right-hand slot. They form Halfbodies that affect the left side of Build's head, his right arm, and his left leg. Inorganic-type Fullbottles (無機物系のフルボトル) are inserted into the left-hand slot, and form Halfbodies that affect the right side of Build's head, his left arm, and his right leg. Any pair of organic and inorganic Fullbottles can be used to create a Trial Form (トライアルフォーム), but each Fullbottle has a Best Match (ベストマッチ) with another one, creating a perfect combination of powers that synergizes well. If they are used together, they create an especially powerful Best Match form.

Each Fullbottle has at least one Best Match with another specific Fullbottle, though individual Fullbottles can have multiple Best Matches depending which Fullbottle is used.

Kamen Rider Cross-Z uses only the Dragon Fullbottle to transform, by inserting it into an adapter called the Cross-Z Dragon, and inserting it into the Build Driver.

Night Rogue and Blood Stalk use the Bat and Cobra Fullbottles respectively to transform by inserting them into the Transteam Gun.

Fullbottles may be inserted into certain weapons such as the Drill Crusher or Beat Closer to activate special finisher attacks. The Lion Fullbottle is used to turn the BuildPhone from phone to bike mode.

Fullbottles can also be utilized to give their users in civilian form temporary superhuman abilities by shaking them (Ex. the Rabbit Fullbottle gives Sento temporary super speed and agility to evade attacks, the Dragon Fullbottle gives Ryuga powerful, fiery punches). Seemingly, the more a Fullbottle is used by someone, the more they synchronize with it.

Design
A regular Fullbottle consists of the following parts: The RabbitTank Sparkling Fullbottle consists of the following parts:
 * Shielding Cap (シールディングキャップ) - The cap on top of the Fullbottle. It is a protective valve that prevents the Transgel Solid inside the Fullbottle from leaking out. This is also why the label on the cap must be turned to face forward during transformation.
 * Material Absorber (マテリアルアブゾーバー) - The component on top of the Fullbottle on which the Shielding Cap is located. It is responsible for absorbing Nebula Gas from the Smash and putting it inside the Fullbottle. Additionally, when Build transforms, the Material Absorber is responsible for retrieving and assembling/disassembling Build's equipment.
 * Transgel Solid (トランジェルソリッド) - The liquid inside the Fullbottle. The liquid activates by stimulus, such as shaking, and when activated forms Build's suit and armor.
 * Clear Mold Bottle (クリアモールドボトル) - The exterior of the Fullbottle, holding the Transgel Solid within. The Bottle is molded in a high strength, lightweight material, and the image cast on it shows the hidden ability inside the Fullbottle.
 * Shielding Tab (シールディングタブ) - The tab on top of the Fullbottle. When pulled, the transformation system starts, and the RT-SP Connector (RT-SPコネクター) pops out at the bottom of the bottle, which feeds the ingredients inside the bottle into the Build Driver.
 * Material Absorber SP (マテリアルアブゾーバーSP) - A component absorbing device attached to the Bottle. When Build transforms, it retrieves and re/disassembles equipment. Located inside the Build Logo imprinted section of the can above the Sparkling Indicator.
 * Sparkling Indicator (スパークリングインジケーター) - The light emmiting component of the bottle that takes the shape of Build's eyes. It shows the state of each component inside the bottle and emits light when the components are activated.
 * Hard Metal Can (ハードメタルカン) - Exterior metal plating that makes up the exterior of the can to protect the internal components. Inside is an inner tank filled with a foam substance called Best Match Liquid (ベストマッチリキッド) which was developed using the Transgel Solid of the Rabbit and Tank Fullbottles and combining it with residue emmited from the Pandora Box. The Best Match Liquid is added as a material for suit and armor (most likely the white sections of the RabbitTank Sparkling Form) and enhances the performance of equipment.
 * Material Activator (マテリアルアクティベイター) - A vibration amplification device built into the Bottle. When shaking the bottle, the Material Activator amplifies the kinetic energy of the shaking and allows the components inside the RabbitTank Sparkling Fullbottle to activate faster.

Unused Fullbottles
Hacking the DX Build Driver toy reveals sounds for Fullbottles currently not set to be used as real forms or toys and have no Best Match counterparts either.
 * Shimauma (シマウマ)
 * Kangaroo (カンガルー)
 * Salt (サルト)
 * Hammer (ハンマー)
 * Hasami (ハサミ)
 * CD (シーディー)
 * Spanner (スパナー)
 * Ichigo (1号)
 * Kuuga (クウガ)
 * Agito (アギト)
 * Ryuki (龍騎)
 * Faiz (ファイズ)
 * Blade (ブレイド)
 * Hibiki (響鬼)
 * Kabuto (カブト)
 * Den-O (電王)
 * Kiva (キバ)
 * Decade (ディケイド)
 * Double (ダブル)
 * OOO (オーズ)
 * Showa Rider (昭和ライダー)
 * Heisei Rider (平成ライダー)

Unused Best Matches
The DX Build Driver also contains sounds for Best Matches that have yet to be used in the show. Some of these Best Matches already correspond to existing Fullbottles used in the show or released as toys, while others use Fullbottles which have yet to be even revealed.

Released Fullbottles= Unreleased Fullbottles=
 * Spider (スパイダー) & Reizoko (冷蔵庫): "Are you Ready? Reikyaku no Trap Master! SpiderCooler! (冷却のトラップマスター! スパイダークーラー!) Yeahhh!"
 * Obake (お化け) & Magnet (マグネット): "Are you Ready? Samayoueru Chouinryoku! (彷徨える超引力!) MagGhost (マグゴースト)! Yeahhh!"
 * Hachi (ハチ) & Sensuikan (潜水艦): "Are you Ready? Shinkai no Shigotojin! HachiMarine! (深海の仕事人! ハチマリン!) Yeahhh!"
 * Sai (サイ) & Dryer (ドライヤー): "Are you Ready? Jounetsu Tairiku! SaiDryer! (情熱大陸! サイドライヤー!) Yeahhh!"
 * Shika (鹿) & Pyramid (ピラミッド): "Are you Ready? Ōke no mamorigami! ShikaMid! (王家の守り神! シカミッド！) Yeahhh!"
 * Penguin (ペンギン) & Sukebo (スケボー): "Are you Ready? Mizu no suberi-gei! PenguinSkater! (水のすべり芸! ペンギンスケーター！) Yeahhh!"
 * Turtle (タートル) & Watch (ウォッチ): "Are you Ready? Toki o kakeru katchū! TurtleWatch! (時を駆ける甲冑! タートルウォッチ！) Yeahhh!"
 * Bat (バット) & Engine (エンジン): "Are you Ready? Ankou no Kidou-ou! BatEngine! (暗黒の機動王! バットエンジン!) Yeahhh!"
 * Crocodile (クロコダイル) & Remocon (リモコン): "Are you Ready? Mizugiwa no Denpa yarou! CrocodiCon! (水際の電波野郎！クロコダイコン!) Yeahhh!"
 * Ghost (ゴースト) & Ex-Aid: "Are you Ready? Batchi Level Up! GhostEx-Aid! Yeahhh!"
 * Gaim (ガイム) & Drive (ドライブ): "Are you Ready? Kajitsu no Top Gear! GaimDrive! Yeahhh!"
 * Wizard (ウィザード) & Fourze (フォーゼ): "Are you Ready? Maho no Uchu Ryoko! FourzeWizard! Yeahhh!"
 * Kyouryuu (恐竜) & F1 (F1): "Are you Ready? Onsoku no Teiou! (音速の帝王! F1サウルス!) Yeahhh!
 * Kappumen (カップ麺) & Energy Drink (エナジードリンク): "Are you Ready? Soukou Genki! CupEnergy! (即効元気！カップエナジー!) Yeahhh!"
 * Kamen Rider (仮面ライダー) & Super Sentai (スーパー戦隊): "Are you Ready? NichiAsa Saikou! Super Hero Time! Yeahhh!"
 * Buttobasoul (ブットバソウル) & Ganbarizing (ガンバライジング): "Are you Ready? Kikaijikake no Touginjou! ButtobaGanba! Yeahhh!"
 * Keisatsukan (警察官) & F1 (F1): "Are you Ready? Drive! (Upbeat jazz music)"