This topic provides a brief overview about USB bulk transfers. I have for a long time been wanting to do a Custom USB class driver on the RT106x devices.Each USB transfer is one packet, which can be up to 64 bytes if using bulk type. If you want to send more than 64 bytes, you have to use multiple packets. Individuals applying for new service or changes to existing services should call Customer Service at 1-800-549-3802. I'm attempting to use bulk transfers to use the maximum allowable amount of free bandwidth when the bus isn't busy for data transfers. Bulk Transfers are used for data which are not of the type Control, Interrupt, or Isochronous. Kingston's XS1000 external SSD is an incredibly convenient file backup solution. Its sleek, compact form factor is designed to fit. Compact, pocket-sized form factor.