Pretty small, waterproof, and not sooo slow. The write speed sequential I find still good. I am happy. My test values for JetFlash510s 32GB (FAT32, USB 2.0): - 26.0 / 11.5 MB / s USB 2.0 Win7 sequence read / write - Write 8.9 MB / s USB 2.0 Linux Dreambox sequence - The write speed for small files is however extremely slow (Similar also Transcend JetFlash520s 64GB, Transcend Micro SD Class 10 32GB) - See picture CDM-2014-0305-Transcend JetFlash510s-32G.png