Sennheiser HD 4.40 BT Wireless Bluetooth Headphones 506782, NOB The new Sennheiser HD 4.40 Wireless offers high-quality wireless sound for every day listening on the move. The closed-back, around-ear headset features Bluetooth 4.0 and aptX compatibility to deliver true Hi-Fi sound with a satisfyingly dynamic bass. Its elegantly minimalistic design has been crafted from robust, high-quality materials to meet the requirements of the street. Specs Product Type: Headset Earpiece Design: Over-the-head Earpiece Type: Binaural Minimum Frequency Resp