soundcore Sleep A20 does not support active noise cancelling (ANC). If the Noise Blocking is not working as expected, there are several ways to improve the Noise Blocking effect.

1. Please note that these earbuds do not support active noise canceling, it is through the matching of ear tips and ear wings that enhances the effect of noise isolation, when you feel that the noise-blocking effect is not good enough, you can try different ear wings and ear tips.

2. Please refer to Wearing Guidance to confirm that you are wearing the earbuds correctly.

3. Please make sure you choose the sealed ear tips, please note that Breathable ear tips are not noise-blocking.