Saw this, thought I would post it...
Coin size, smaller than a US quarter.
List of Compatible Android Smartphones & Tablets
Due to hardware and software limitations of many Android devices -- especially older ones, this card reader is only compatible with the following tested and verified devices. It will ONLY work with devices listed here.
- Samsung: Galaxy S2, S3, S4, Note, Note 2, Note 3, Mega; Galaxy Express, Galaxy Tab 3 10.1, Galaxy Note 8.0.
- HTC: One, One Mini, First, One X+, Evo 4G LTE, DROID DNA.
- Motorola: Moto X, Droid Mini, Droid Ultra, Droid Maxx, RAZR M, RAZR HD, RAZR MAXX HD, Xyboard 8.2" Tablet.
- Google: Galaxy Nexus, Nexus 7 (2012 Original & 2013 New), Nexus 10; all require third-party software or device being rooted.
- Sony Xperia Z;
- LG: G2, Optimus G Pro
- Asus MeMO ME171.
- Xiaomi: 1S, 2, 2S, 2A, Xiaomi Box; Meizu: MX, MX2;
- Huawei: Ascend D2, Mate;
- Lenovo K900
- Google Nexus 4 doesn't support USB-OTG, it is NOT compatible.
- Dimensions: 0.8"x0.9"x0.3" (21x23x8mm)
- Outer dimensions when plugged-in: 0.8"x0.6"x0.3" (21x16x8mm)
- Weight: 0.1oz (2.7g)
- Interface: USB Micro-B, USB 2.0
- SD card supported: MicroSDHC up to 32GB, MicroSDXC up to 64GB (max available today) and higher (future).
- Power consumption: 0.25w
- PC compatibility: Windows XP/Vista/7/8, Mac OS X, Linux 2.6 and up; using USB-to-MicroUSB adapter (included).
- Smartphone/Tablet requirement: Android 4.0 and up with power-enabled USB-OTG hardware capability and USB Mass Storage support in software.