Headphones are essentially two small speakers worn over the ears on the head by a person. Headphones function as electroacoustic transducers, transforming electrical signals into sound. Ear speakers and earphones are alternative names for them. Headphones that are around the ear or over the ear feature a headband that secures the speakers on top of the head. The feature that wireless headphones need most is noise cancellation. Most headphones use active noise-cancellation technology with preset filters to eliminate background noise. Some wireless headphones have adaptive noise cancellation, changing the audio to help block out noise. The growth of the Wireless Headphones market is fuelled by the use of apps for controlling the headphones, innovative design and technology, and the increasing popularity of wireless headphones.