Anker's Soundcore Sleep Earbuds 4 Pro Add In-Ear PPG Sensing and Adaptive BioSync Audio

Anker's Soundcore Sleep Earbuds 4 Pro, arriving in November at $349.99, incorporate an in-ear PPG sensor tracking heart rate, HRV, stress, and fatigue. The data drives BioSync, which plays adaptive soothing audio to help users fall asleep — moving the device beyond passive sound masking toward active sleep intervention. The standard model ($229.99, October) omits the sensor.