In a joint venture with SanDisk, Sony released a new Memory Stick format on February 6, 2006. The Memory Stick Micro (M2) measures 15 × 12.5 × 1.2 mm (roughly one-quarter the size of the Duo) with 64 MB, 128 MB, 256 MB, 512 MB, 1 GB, 2 GB, 4 GB, 8 GB, and 16 GB capacities available. The format has a theoretical limit of 32 GB and maximum transfer speed of 160 Mbit/s. However, as with the "PRO Duo" format, it has been expanded through the "XC" series as "Memory Stick XC Micro" and "Memory Stick XC-HG Micro", both with the "theoretical" maximum capacity of 2 TB.