Cognitive Kit
http://www.diytdcs.com/tag/cognitive-kit/
https://www.reddit.com/r/tDCS/comments/2be91o/the_cognitive_kit_is_available/
Note: The webpage of the device does not work at the moment but it should be: http://www.cognitivekit.com
blog post: https://speakwisdom.wordpress.com/2014/07/31/the-cognitive-kit-stealth-tdcs/