Great capacity. VERY SLOW transfer rate. For a USB 3.1/3.0 flash drive it transfers slower than a 2.0. My speeds with my other 3.0 rated flash drives hover around 30 - 40 Mb/s. This drive starts of great for the first two minutes. Then it slows to a crawl of 3 - 4 Mb/s. I've heard the 16/32/64 capacity drives work great. My 128GB Silicon Power Blaze B02 USB3.1 Flash Drive works unacceptably poorly.