sparklers
Wunderkerzen is the German word for sparklers. They are hand-held fireworks that emit showers of sparks when lit. They are commonly used at celebrations such as New Year's Eve and birthday parties. In German-speaking countries, they are also popular at festivals and other outdoor events.
I bought sparklers for your birthday cake.
It's customary in some cultures to use small sparklers instead of candles on a birthday cake. The speaker here is telling someone that they bought sparklers for that person's birthday.
Many people light sparklers on New Year's Eve.
Sparklers are a common firework used to celebrate New Year's Eve. This sentence is highlighting a cultural practice of using sparklers as part of New Year's celebrations.
It was dark, but the sparklers helped us find the way.
The sentence conveys a situation where sparklers were used in the dark to light up the path or way, suggesting their illuminating effect in darkness.