Check the listing for details. Apogee Symphony I/O MKII Thunderbolt Option Card. Condition: New. Listed at 399.00 USD. Symphony’s I/O modules are designed to future-proof your investment in flagship Apogee sound quality. If you own an original Symphony I/O, the Symphony I/O Mk II chassis can increase the longevity of your system by offering backwards compatibility with first generation 2×6, 8×8, 16×16 and 8 channel mic preamp I/O modules.Thunderbolt Option CardSymphony I/O Mk II Thunderbolt is the most powerful multi-channel audio interface for Thunderbolt-based Mac workstations. Designed for the home or professional studio running Logic Pro X or any other native based DAW, this system offers your choice of 4 different base I/O configurations with the option to expand up to 32×32 simultaneous channels per unit while still maintaining incredibly low latency.