|This article is about a/an half form in Kamen Rider Build.|
In any form that uses the Rocket Fullbottle, Build is armed with the Space Ride Arm (スペースライドアーム Supēsu Raido Āmu) on his left arm that can combine with the BLD Rocket Shoulder (BLDロケットショルダー BLD Roketto Shorudā) to form the Cosmo Builder (コスモビルダー Kosumo Birudā) assault rocket/missile, which can fly off as a rocket and ram the opponent, and let him fly.
The Rocket Halfbody is composed of the following parts:
- Astro Head Armor (アストロヘッドアーマー Asutoro Heddo Āmā) - The light blue head armor. It is extremely sturdy, and is able to withstand collisions with space debris. An air tank is installed inside to allow the user to breathe in outer space.
- Right Eye Rocket (ライトアイロケット Raito Ai Roketto) - The eyepiece. A 3D radar and navigation system is installed to increase the user's survivability in outer space.
- Booster Face Module (ブースターフェイスモジュール Būsutā Feisu Mojūru) - The 'rocket flame' piece protruding from the Right Eye Rocket. It controls and operates the Cosmo Builder when it is launched from the left arm.
- Astro Chest Armor (アストロチェストアーマー Asutoro Chesuto Āmā) - The light blue chest armor sections. It is extremely sturdy, and is able to withstand collisions with space debris. An air tank is installed inside to allow the user to breathe in outer space.
- BLD Rocket Shoulder (BLDロケットショルダー BLD Roketto Shorudā) - The right shoulder armor. It is a large rocket engine equipped with a large thrust composite engine that allows the user to propel themselves through space at high speeds. It can also combine with the light blue armor parts of the left arm to form the Cosmo Builder (コスモビルダー Kosumo Birudā) assault rocket, a rocket-like missile that can return to the user.
- Space Ride Arm (スペースライドアーム Supēsu Raido Āmu) - The lower left arm armor. A rocket thruster meant for attitude control is built in, allowing the user to fly and fight freely in outer space. It also allows the user to deal heavy accelerated punches. It can combine with the light blue left arm armor to form the Cosmo Builder.
- BLD Rocket Glove (BLDロケットグローブ BLD Roketto Gurōbu) - The reinforced hand. By utilising a built in laser irradiation device, it can safely remove any surrounding space debris.
- BLD Unlimited Suit (BLDアンリミテッドスーツ BLD Anrimiteddo Sūtsu) - The shock-resistant bodysuit. Along with protecting the wearer’s body, there is a limiter installed that can be released to bring out full physical ability.
- Space Ride Leg (スペースライドレッグ Supēsu Raido Reggu) - The right leg. A rocket thruster meant for attitude control is built in, allowing the user to fly and fight freely in outer space. It also allows the user to initiate quick accelerated kicks.
- Aero Shell Shoe (エアロシェルシューズ Earo Sheru Shūzu) - The right foot. It is highly impact resistant thanks to highly rigid parts, and due to this, it can easily distort an enemy's internal frame with one kick. Additionally, it can deploy a protective aeroshell around the user's entire body to protect them from friction created during re-entry.
- Kamen Rider Build
- RocketPanda (Build Episodes 7-8, 15, 18, 20)
- GorillaRocket (Build Episode 8)
- UnicornRocket (Kamen Rider Battle: Ganbarizing)
- OrangeRocket (Kamen Rider Battle: Ganbarizing)
- ObakeRocket (Kamen Rider Battle: Ganbarizing)
- Rider Slash: Build surrounds the enemy with a white, oval-shaped energy chart, then uses the Space Ride Arm to fly at the enemy and performs a series of slashes with the Giant Scratcher. The chart goes up as Build continues to slash the enemy.