Comptia A+ consisting of A+ Essentials exam and A+ Practical exam is the most widely known certification in the area of computer hardware and operating systems. The swregn.com Comptia aplus android app consists of both A+ Essentials and A+ Practical exams with 400+ questions each. The app is available on both android and iphones in respective googleplay and iTunes stores. 

Website

http://www.swregn.com/android/download/cisco/Exam-Simulator-CCNA.html