MyAppSharer let you to easy share your apps to your friends or backup, you can share by link of Google play or directly share APK (App's full package).
MyAppSharer support many method to share your apps, you can share by message, Gmail, bluetooth, what's app, facebook, QR-Code, Dropbox etc..
By using the feature to export APK to SD card, you could backup your app to your SD card.
MyAppSharer also support share multiple apps at one time, and support instant search, easy to find your apps.

Here is a demo video for sharing apk between devices.
Thanks "Flo WolfOne" provide the video.
https://www.youtube.com/watch?v=ETuLrn3QK2U

* Nexus devices could not receive APK via Bluetooth, to workaround this issue, please use "Android Beam" or "Bluetooth(zip)" instead.

p.s.
1. You can install "Barcode scanner" to support share link by QR-Code.
2. Install "Dropbox" to support share APK to Dropbox.
3. If you like the app, you could donate the app from settings menu to remove Ad.

Disclaimer: Before share APK, please make sure you have the redistribution right.

Recent changes:
2.3.2
Sort by APP name when sharing multiple APPs

2.3.0
Add APP name to subject when sharing by tap app directly.

2.1.0
* Enhance UI for choosing sharing methods
* Fix crash issue on some devices

2.0.1
Quick fix errors on Android 4.1.

2.0.0
All new Material Design UI.
Fix errors when using Bluetooth(zip) option.

1.8.0
Support to share link/APK via Android Beam.
(Nexus devices could not receive APK via Bluetooth, please try to use Android Beam or Bluetooth(zip) instead)