
Everything I've tested so far (6 out of 20) has worked. They are all 4GB as described. Other reviews say that the read/write speeds are poor, which I can confirm with a tested write speed of 5 MB/s and a read speed of 23 MB/s. That's enough for my purposes: I just share small files with friends and family without having to worry about returning the disc.

Kingston DataTraveler SE9 32GB USB 2.0 Flash Drive for Reliable Data Storage (DTSE9H/32GBZ)
69 Review

Titan Gray Samsung BAR Plus 256GB USB 3.1 Flash Drive (MUF-256BE4/AM) with Up to 400MB/s Transfer Speed
69 Review

Compact and Convenient: SanDisk Cruzer Fit USB 32GB Flash Drive (SDCZ33-032G-A11)
66 Review

Sandisk Ultra Flair 128 GB Silver USB Flash Drive: Reliable and High-Speed Storage
65 Review

8TB Seagate Backup Plus Hub Desktop Hard Drive with Data Recovery Services
56 Review

18 TB External HDD Western Digital WD Elements Desktop, USB 3.0, black
95 Review

π Seagate Expansion 3TB Portable USB 3.0 External Hard Drive (STEA3000400) in Black
60 Review

2 TB External HDD ADATA DashDrive Durable HD650, USB 3.2 Gen 1, Blue
55 Review