For my FiiO X3 Digital Music Player (3.5 mm Headphone Output Jack) I searched for a memory card, which was still relatively low and at the same time had a fairly large storage capacity. Both I purchased this product from Samsung and am very satisfied with the quality and the processing speed when synchronizing my music on the memory card.
Also, the player works just fine with the memory card and bleats not even fast song title changes are possible, intervening without slow load times and no hangers. Thus, the investment has paid off for me and maybe there will soon be a version with 128 gigabytes of storage capacity that I will buy myself of course.