Filibuster's Fireworks are a well-known brand of magical fireworks sold in the wizarding world. The full product name mentioned in the books is Dr. Filibuster's Fabulous Wet-Start, No-Heat Fireworks. Their physical appearance is not described in the novels, but their descriptive name provides significant information about their magical properties. They are presented as a popular novelty item intended for amusement and are presumably safe enough for young wizards to purchase and use.
The primary magical properties of these fireworks are advertised directly in their name, distinguishing them from ordinary Muggle pyrotechnics:
They are used for entertainment, pranks, and celebrations, offering a magically enhanced and safer alternative to traditional fireworks.
The history of Filibuster's Fireworks is not documented in the novels. By 1992, they were an established and popular product available for purchase in shops located in Diagon Alley.
Filibuster's Fireworks play a minor but notable world-building role in Harry Potter and the Chamber of Secrets. After Harry Potter accidentally uses the Floo Network to travel to Borgin and Burkes in Knockturn Alley, he successfully navigates his way to the much more welcoming Diagon Alley. While contemplating his newfound freedom, he thinks about things he could buy, including “a pack of Dr. Filibuster's Fabulous Wet-Start, No-Heat Fireworks”. This brief mention serves two purposes. First, it effectively contrasts the light-hearted, fun magical items of Diagon Alley with the sinister Dark Arts artifacts he just witnessed. Second, it establishes the concept of magical fireworks within the series, a concept later expanded upon significantly by Fred Weasley and George Weasley with their own impressive creations, such as Weasleys' Wildfire Whiz-bangs.