USB flash sticks/drives whatever, everyone want one, and a big one (128 GB +). However, to run an OS from, they are not much use (unreliable, no TRIM, limited lifetime), see Running OSX of USB 3.0.
Much better and cheaper, is an SSD drive, be it 3.5″, 2.5″ internal or external. These can be used as an OS disk sans problèmes, with none of the disadvantages listed above.
However, these are quite large, compared to a USB stick. Also, an external will have a slower interface that using an internal SATA3. Likewise, an internal can’t quickly be connected to another computer via an external USB, unless you have a USB to SATA cable.
However, most manufactures will have a M.2 equivalent of their 2.5″ internal SATA SSD drives. Now, an M.2 SSD can be put into a small-ish external USB-C enclosure, as well as an internal 2.5″ SATA enclosure. The best of both worlds… you can take your internal 2.5″ SSD out, pop out the M.2 SSD and pop it into a small USB device to carry about, with no real loss of performance, if you use a USB 3.x port.
Instead of getting a USB flash drive, think about getting an M.2 SSD and USB-C adapter.
Instead of getting an 2.5″ SSD drive, think about getting an M.2 SSD and 2.5″ SATA adapter.
That said, it is then a massive headache to get the correct enclosure matched to the correct M.2 SSD (SATA vs NVMe).
… one option is to use a Seagate Backup Plus hub, big (at up to 10 TB) but noisy, or at least noisier that passport external disks). Also, according to this cnet review, if the drive is plugged into a USB 2.0 port then the built-in USB 3.0 hub does not work correctly, and may not detect what is connected to it. Also the price is about the same as two “fat” 5 TB passport drives.
Another option is an actual USB hub, although I tried that (see Lexma) which was a powered hub and I ended up with a broken inaccessible partition
It’s one of those horrifically dangerous 2.5×2.5×2.5 cm mini-cube singe port 1 A USB chargers. There were scorch marks on the base of the case. The circuit was very simple, a simplified SMPS on two small PCBs… which held into the cube casing with white silicone/glue – scratch that away and it is easy to extract the pair of PCBs
Whilst looking into the XTAR battery chargers, I came across the XTAR EU4, which offers QC3.0, 2 x USB 2.4A and USB C (PD) ports… and although the QC and PD capability is a bit limited, it’s not by much (i.e. QC 3.0 does not have 20V capability, and PD current is limited to 20V 2.25A (45W))…
Looking for an internal 2.5″ 2TB HDD for your MacBook, or MacBook Pro? The cheapest option is to get a Seagate Backup Slim (STDR200020x where x=0/1/2/3) USB external disk and rip its guts out. It is the only 9.5 mm high, 2.5″ 2TB internal disk on the market (or was in 2015), and I believe that it still is – even in late 2017.
In Bangkok, an internal disk such as a Seagate Barracuda ST2000DM006 2TB 64MB Cache SATA III 6.0Gb/s is around 3350 baht, or more precisely:
Seagate Barracuda SATA III 128 MB 7 mm 2Y 3390 Baht
Seagate Firecuda SATA III 128 MB 7 mm 5Y 3850 Baht
whereas the Seagate Backup Slim is normally 2620/2590 baht (depending on where you shop), or 2360 baht on offer (I actually ended up paying 2290 baht at a sale, with a soft case and a OTG mobile adapter thrown in).
Other disks are too fat (i.e. tall) at 12 mm, or 15 mm, to fit in the MacBook internal disk bay. other heights may be 6 mm, 7 mm (ST2000LM00x, where x=3/7).
The STGD2000400 is physically the same disk (9.6 mm thick), but it is pre-formatted for the PS4. There is also an XBox formatted disk (SRD0NF1/STEA2000403), although, as the external case is 14.8 mm thick, the disk itself may be oversized – note that the external case of the Backup Slim is 12.1 mm.
Also covered are the Seagate Backup Plus Fast, and Seagate Backup Plus.