This audio is great way to improve your vocabulary quickly. A question is asked and almost immediately answer is given. In less than 1 hr around 500 questions are covered. The great thing about this is the words asked not only cover GRE, TOEFL, GMAT words but also words frequently used in newspapers, movies, novels etc. Listen multiple times for maximum benefit.
The zip file also contains a .db file. This is for folks who have android phones. Download Anymemo software and open this file in that program in your android phone. Anymemo is a flashcard software similar to supermemo which increases effectiveness of your learning by spaced repetition method. If you don't have android phone but have any other smartphone then you can use the .txt file. Just google out how to convert it into flashcards for your mobile.