USB 3.0 SD Card Reader, Rocketek 2 Slots Memory Card Reader with a Build-in Micro SD Card Cap for SDXC/SDHC/UHS-I SD Cards, TF/Micro SD Cards Reader - Take It as a USB 3.0 Flash Drive

TL;DR: Rocketek makes great USB 3.0 card readers!Rocketek produces several card readers that look alike, but don't necessarily behave alike. The models I will be covering are the RT-CR2, RT-CR3A, RT-CR5 and RT-CR6 USB 3.0 memory card readers. If you read the Q & A sections for these card readers you will find that more than one person has asked if they can use 2 cards at once, and the answers were, yes, no, yes, no, yes, no ...??? So here is the info on these models that will clear up the confusion.The RT-CR2, CR3A and CR6 all look nearly identical. They all have a rotating USB plug cover and a door at the end that covers a MicroSD and full size SD slot pair. The CR2 has an additional pair of slots on the side (4 slots total on the CR2). All three of these models are a little bulky and will likely block adjacent USB ports if they are close together.Rocketek RT-CR2:With the RT-CR2 you can use 2 cards at once if you put one in a side slot and the other in a rear slot (under the door). It will appear to your computer as 2 card readers, and Windows will assign each card its own drive letter. In spite of it having 4 slots in total, you cannot use more than 2 cards at once. Think of each SD+MicroSD slot pair as a single slot that will accept either a full size or micro size SD card. The CR2 is the most versatile, because you can use any combination of 2 cards without any additional adapters (SD+SD, SD+Micro, Micro+Micro).Rocketek RT-CR3A:The RT-CR3A looks like a CR2 with rounded shoulders, and without the additional side slots. It has the SD+MicroSD slot pair under the door, but you can only use 1 card (slot) at a time. Like the CR2, both slots are wired in parallel, so they are really just a single slot that can accept either size card. Your computer will only see a single card reader, and will only assign a single drive letter.Rocketek RT-CR6:The RT-CR6 looks exactly like the CR3A, but the slots are not wired in parallel, so you can use both at once. Your computer will see 2 card readers, and Windows will assign each card its own drive letter. It's not as versatile as the CR2 because it can only pair a full size SD and a MicroSD card, or 2 MicroSD cards with one card in a full size SD adapter. The CR2 can also do 2 full size SD cards, and doesn't require an adapter for a second MicroSD card. The advantage of the CR6 over the CR2 is that it's a little thinner (10mm/0.4" vs 15mm/0.6") and a little less expensive (the price difference was only 30 cents at the time of this review).Rocketek RT-CR5:The RT-CR5 is a smaller card reader which functions like the CR3A. It has one full size SD card slot on the side, and one MicroSD card slot at the rear under the door. Like the CR3A, you can only use a single card at a time, but the CR5 is much slimmer than the others so it will fit into closely spaced USB ports without blocking access to adjacent ports. Do note that you can only fit a MicroSD card under the cover. A full size SD card will stick out one side, so when using a full size card, it might interfere with another USB port on that side (of course if you put the CR5 into that port it won't be a problem).I personally own the RT-CR2 and the RT-CR5, and they are both amazing card readers. They have very fast read/write speeds that seem to only be limited by the SD card itself. Of course you will need a fast SD card to see fast speeds (no card reader can miraculously make a slow card fast).When I used CrystalDiskMark to test a Samsung Pro MicroSD card in the Rocketek, I got read speeds of nearly 90MB/second and write speeds of nearly 80MB/second. That's what the manufacturer rates the card at, so I have yet to find an SD card fast enough to see the limit of the Rocketek. In fact, the scores with the Samsung Pro card in the Rocketek USB 3.0 reader were slightly higher than the same card in my computer's built-in SD card slot!Even when used on USB 2.0 ports these card readers perform well, they are faster than any USB 2.0 card reader I have tested.Other than the somewhat bulky size of the RT-CR2 (necessary for its versatility), my only other gripe is that the rotating USB plug cover is too loose and doesn't offer much protection. The rotating cover on the smaller RT-CR5 is much firmer and has stronger detents, so it actually does offer some protection.When I purchased the RT-CR2 a few years back I was dealing mostly with full size SD cards, and only occasionally with MicroSD cards. The RT-CR2 was the best choice for its versatility. Now I find myself in the opposite situation. I'm dealing almost exclusively with MicroSD cards, and rarely with full size SD cards. So I purchased the slimmer RT-CR5 and I’m loving the smaller form factor. It fits into closely spaced USB ports, even when the other ports are populated with USB cables, wireless dongles and whatnot. I still use the CR2 when I need to copy data from one card to another, but the Rocketek RT-CR5 is my new go-to card reader of choice!Rocketek RT-CR5 USB 3.0 Memory Card ReaderRocketek RT-CR2 USB 3.0 Memory Card Reader (4 slots, 2 cards)One final note on compatibility. I have used these card readers on multiple Intel x86/x86-64 Windows and Linux machines in both USB 3.0 and USB 2.0 ports, and on the USB 2.0 ports of the ARM based Raspberry Pi running Raspbian Linux, and even on my Samsung Galaxy Note 4 Android phone using a small OTG adapter (Rocketek even sells the RT-CR5A for a dollar more, which is a CR5 with an OTG adapter included).They just seem to work with everything.

Should work with micro sd or regular sd in the side slot!

It functions just fine, but the protector part snapped in half very quickly. Perfectly usable though

Sturdy and highly portable these little guys are great. I use many Micro SD cards and needed a way to write to multiple cards at the same time. So I bought 4 of these. They worked right of the bat. No hassle, no fuss. With Windows 8.1 and a 10 port USB 3 hub, I found i could transfer files to all 4 of my new card readers at the same time. I was not able to use more than one card with each reader at a time. But I didn't need to as a had 4 of them working at the same time anyway. These are so small and easy to transport I love them :)

Has worked flawlessly so far between mac and android. The cover over the micro slot at the end is likely going to be the first part to fail. Also, the cover that swivels over the USB leaves a big gap when closed allowing debris to get inside. On the upside, it's inexpensive and works as advertised.

Device is exactly as described, is well designed, and works at high transfer speeds with any of the 3 input cards. The first one I received had the USB connector slightly mis-aligned, it was off plum by 10 degrees. This made using in in closely places USB slots a bit too snug, so I returned it and ordered a new one to replace it. The device worked perfectly, simply the USB connector was not in straight alignment with the body of the device. I anticipate the replacement will be correctly aligned.Added information- I did receive a replacement and the alignment of the USB connector with the body was square and plumb. As before the device works fine.

Cheaply made and perfomance is more USB2.0 than USB3.0.Out of the box the USB connector was bent and the finish is sub-par.Performance wise is just slightly higher than any cheap USB2.0 card reader.That is of course when it works...For some reason sometimes it refuses to work on the USB3.0 slot and only works on the USB2.0:The file transfer just stops and the card reader is not recognized, but it will still work on the USB2.0 slot.Bad buy for me...

This adapter is awesome. It's light and feels pretty durable for a little plastic USB drive. It has a micro SD card slot (what I bought it for) as well as mini SD, normal SD/SDVX/MMC slots. I can't speak to the specs of the drivers inside it, but I know it allowed me to transfer 80 GB of movies from my external hard drive to a micro SD card in a little less than 30 minutes. And as a little bonus, the cap on the end that covers the micro SD slot can latch closed even with a micro SD card plugged into it. That gives me a little peace of mind that if I ever leave my micro SD plugged into it, it won't fall out or get lost. I highly recommend this adapter for making SD cards USB compatible.