Apogee Symphony I/O Mk2 TB 32x32, Modular Audio Recording Interface, Chassis including 2 I / O modules, Module 1: 16 x 16 analog I / O (Mk II), Module 2: 16 x 16 analog I / O (Mk II), 1 Module slot for optional system expansion (eg ProTools HD), Dual multi-function encoder, Intuitive user interface with touch display, 1 Independent headphone output, Stand-alone functionality, 2 Thunderbolt connections, Downward compatible with all I / O modules from the first generation symphony, Compatibility: Thunderbolt Mac OS 10.9.5 and higher, Format: 19 ""/ 2U, Dimensions: 450 x 292 x 89 mm