Update: died after receiving and using 3 of them! Slowly to your work, then death. It must be USB 2.0. However, they transfer data more slowly than older USB 1.0! I've tried all 4 and they have very low data rates. In addition, if you write to one of them, there is a delay of about 4 seconds before anything is transmitted. I use flash drives all the time and usually 5-6 a day. Those are the only ones I have that have this problem.
Compact and Convenient: SanDisk Cruzer Fit USB 32GB Flash Drive (SDCZ33-032G-A11)
66 Review
Samsung BAR Plus 128GB - High-Speed USB 3.1 Flash Drive Titan Gray (MUF-128BE4/AM)
67 Review
Kingston DataTraveler SE9 32GB USB 2.0 Flash Drive for Reliable Data Storage (DTSE9H/32GBZ)
69 Review
Sandisk Ultra Flair 128 GB Silver USB Flash Drive: Reliable and High-Speed Storage
65 Review
2 TB External HDD Western Digital WD Elements Portable (WDBU), USB 3.0, black
84 Review
Shock-Resistant Transcend StoreJet 25M3 USB 3.1 Slim Portable Hard Drive with 500GB Capacity
99 Review
18 TB External HDD Western Digital WD Elements Desktop, USB 3.0, black
95 Review
2 TB External HDD ADATA DashDrive Durable HD650, USB 3.2 Gen 1, Blue
55 Review