Astell&Kern Angie II in-Ear Monitors by Jerry Harvey Audio - 8 Drivers per Channel, 4th Order Crossover, and Full Metal Housing Custom-made Proprietary Dual low, Dual Mid, Quad High balanced armature drivers per side (8 drivers per side), Variable bass output, adjustable from cable : user controlled low frequency drivers with the adjustable bass (0 - +10dB), Frequency ranges from flat bass response up to +10dB (10Hz to 100Hz) Integrated 4th Order crossover and Triple Bore with Stainless Steel Tubing, Noise Isolation up to -26dB Includes both 3.5mm unbalanced and 2.5mm balanced cables by Moon Audio