Key Features of the SanDisk Extreme 64GB 150MB/s SDXC UHS-I Memory Card 64 GB of storage UHS-I, V30, U3, and Class 10 Max Capacity Speed of Reading: 150 MB/s Max Speed of Writing: 60 MB/s Min Speed of Writing: 30 MB/s Documents Features of the Integrated Write-Protect Switch for Full HD, 3D, and 4K Video Amount One SDXC card type for storage 64 GB of capacity Video Speed Class V30 Bus Type UHS-I Speed Class 10 UHS Speed Class U3 Maximum Read Speed: 150 MB/s Maximum Write Speed: 60 MB/s 30 MB/s is the minimum write speed. Is there a built-in write-protect switch? Ability to Connect Wirelessly Not in the box 64GB Extreme UHS-I SDXC Memory Card from SanDisk