Dual Micro SD TF to MS Pro Duo Card Adapter 2 Slot Supports 2 MicroSD/MicroSDHC TF cards even different capacity can be used. Support OS: Windows Vista/XP/2000/Me/98SE, Mac OS 9.2, Mac OS X, Linux. Support Capacity: MicroSD 256MB - 2GB / MicroSDHC 4GB - 16GB. Speed: Super high read/write speed of 10 MB/s and up. Size: 32mm x 20mm x 1.6mm.