ATH-CKS50TW truly wireless headphones combine advanced acoustic technology for stunning bass with a comfortable and secure fit, while a high-capacity battery provides up to 20 hours of powerful, continuous audio (up to 50 hours with the charging case). All you have to do is let the music take control. The newly developed large-diameter drivers (9mm Solid Bass HD TWS drivers) deliver deep bass while the CKS50TW shape provides a snug fit - an important factor for truly wireless headphones as the airtight fit prevents the bass from escaping to deliver a unique and intimate music experience.