Cosmic Suits are specialized armor worn by members of Frieza's race in order to increase their power and combat capabilities.
Cosmic Suits are made by combining the natural Bio Suits of Frieza's race with technology. They increase the power of their user. It can also be used as a way to repair the physical damage to a Frieza's race's member's body after being heavily injured, as members of their race are capable of surviving horrific injuries that would be fatal to most other races. Unlike cybernetic parts and other machines made by humans, however, the Cosmic Suit's mechanical parts are unable to prevent the user from having their ki being sensed.
Video game appearances
In Super Dragon Ball Z, Frieza gains an enhanced version of his Cosmic Suit called Full Armor Mecha Frieza which includes armaments such as a rocket launcher mounted on his shoulder, the ammunition for which are stored behind his other shoulder, he has a belt of explosives around his waist, and his tail is upgraded with additional armor and sharp blades.
In Dragon Ball Online, Cosmic Suits similar to the one utilized by Mecha Frieza are available for Time Patrol members to wear. The Cosmic Suit appears as an outfit for Frieza's race custom characters in Dragon Ball: Xenoverse and Dragon Ball Xenoverse 2.
In Dragon Ball Xenoverse 2, after training in his fifth form, Cooler gains the ability to transform into Metal Cooler, the transformation simply being a metallic Cosmic Suit over his fourth form. A Frieza race Future Warrior can utilize their Cosmic Suit in conjunction with their Turn Golden form. There is also an outfit called Mecha Frieza Suit which is a costume based on Mecha Frieza's Cosmic Suit which can be worn by the Future Warrior regardless of race. If the Lower Body Option is worn by a Frieza Race Future Warrior, their tail will take on the suit's mechanical appearance, making it resemble Mecha Frieza's tail. Like the Frieza's Suit (Final Form) costume, the Mecha Frieza Suit's skin and jewel-like portions will not change color when the Turn Golden Awoken Skill is used (instead they will simply glow brighter).
During Frieza's Siege a Frieza Race Time Patroller named Hiebie wears a Cosmic Suit. However, despite his cybernetics, he states that he is unable to fight due a nasty bug that has made him sick and unable to fight, though it is unknown if he is telling the truth or simply using as an excuse to avoid having to fight the Frieza Force. If true it would imply that a Cosmic Suit's cybernetics do not protect the wearer from contracting diseases.