As the market shifts toward slimmer and thinner solutions, the M.2 is intended to replace mSATA which used the PCI Express Mini Card  physical layout.  
M.2 NGFF product is transforming from PCIe Mini Card to a smaller, standardized form factor used in the industry.
M.2 (also known as the Next Generation Form Factor, NGFF), is now a specification for internally mounted computer expansion cards/add-in cards/modules. It provides the standard interface for solid state drives (SSD) and various wireless cards supporting Wi-Fi, Bluetooth, Global Navigation Satellite Systems, Near Field Communication, Hybrid Digital Radio and WWAN.

Features:

• 67 pins @ 0.5mm pitch
• Support PCI Express 3.0, USB 3.0, & SATA 3.0
• For both single and double-sided modules

Applications:

• Portable Mobile Device
• Tablet, Notebook & Desktop
• Server & Gaming Device
• Device that requires SSDs