Nexus 5 and Nexus 6p Android phones immediately recognized the card reader, brought up ES File Explore, and I was able to look at external storage and video images and video. iPadMini gave me more problems and did not work right out of the box. I had to find an app that would work. I mostly an Android user so the Android behavior is the most important to me. I tried both SD cards from SONY NEX 5 camera and my a trail cam. I am able to view JPG and MP3 file. Note that AVI files are visible but my phone cannot play them back. This is not a problem with cards reader (it showed the files) but rather the limitation of the phone.
The card reader is compact (2" wide), I show it on the 1/2" grid for size reference.
You can find it on Amazon by following this link.
Ali Julia review ★★★★★