This is the 10175th most frequent Russian word.
беспроводная
Wireless.
Here, 'беспроводная' is used as an adjective describing the speaker to indicate that it operates without a wired connection.
Я купил беспроводную колонку для прослушивания музыки.
I bought a wireless speaker for listening to music.
In this sentence, 'беспроводная' qualifies the term 'сеть' to specify that the network functions wirelessly.
Беспроводная сеть позволяет свободное соединение с интернетом.
A wireless network allows free connection to the internet.
The word 'беспроводные' is the plural, short-form adjective describing 'наушники,' conveying that the headphones are without wires in operation.