Apple unveiled its long-rumored AirPod Pro earbuds Monday: For a price of $249, the new model promises to have noise cancellation, as well as a transparency mode that will allow users to let in some ambient noise when they don’t want completely shut out the outside world. AirPod Pros will be available in the U.S. and 25 other countries starting this Wednesday.

Apple integrated 2 microphones into the new AirPod model to power its noise cancellation technology. One of the microphones is said to sample ambient noise, while another measures the noise level inside the ear canal.

Taken together, AirPods generate and balance counter-noise to cancel out any outside noise. This process is being adapted 200 times per second, according to Apple. Apple is providing a way to turn on transparency mode, and let in some level of outside noise, via a software slider on iOS as well as through the on-headphone controls.

Apple was widely expected to introduce AirPods with noise cancellation this fall; some of the hardware for the new model had already leaked this summer, and icons representing the device recently surfaced in an iOS update.