It's free to get the .apk setup package of IIJ SmartKey and you can take a look at users' reviews on Droid Informer. This application installer requires 6 MB of free space to work fine on Android 4.0.3 and higher. The antivirus report shows that the app is totally safe. Internet Initiative Japan Inc. has developed this application that falls into the Tools category.
IIJ SmartKey has been downloaded and set up by over 1K users and its most recent release is dated November 24, 2016. According to the latest data, the app is rated 4.5 on Google Play.