PROMISE Technology today introduced the Pegasus J2, a fast Thunderbolt storage device, capable of delivering up to 750 MB/s in a device the size of a smartphone. Compatible with all Thunderbolt enabled Macs, the PROMISE Pegasus J2 is a pocket-sized, flash-based external storage device that offers up to half a Terabyte of storage and is available in 256GB and 512GB capacities.