The Sleep Earbuds 4 quiets the two noises that keep roughly 20 million US couples awake: ambient sound and a partner's snoring. Enhanced ANC gains 3–5 dB in the sleep-critical 200–800 Hz band, while Twin-Seal dual-layer ear tips isolate above 2 kHz — the two stages covering complementary frequencies. For snoring, an industry-first AI adaptive masking system detects each snore's onset, frequency, and loudness in the charging case and generates masking audio that follows its rise and fall, something static white noise cannot do. The Smart Sensing Case™ resolves the isolation-versus-vigilance trade-off, waking you only for critical sounds like a baby's cry or fire alarm. A sleep-dedicated cavity mapped from a 10,000+ ear database keeps side sleepers comfortable through the night.