GMAT Club Forum is a free Android app that provides a comprehensive GMAT preparation experience. Developed by GMAT Club, the app is designed to help you access thousands of GMAT practice questions, track your performance, and review your progress. With a built-in GMAT timer, you can time yourself while taking practice tests and measure your speed and accuracy.

The app's Error Log feature also allows you to track your mistakes and review them later, ensuring that you don't repeat the same errors. You can bookmark GMAT questions that you want to review later, categorized by Math, Verbal, and PS, DS, CR, SC, RC, making it easier for you to focus on specific areas. Additionally, the app includes the School Decision Tracker, which allows you to track your MBA stats and connect with the 1,000,000-member strong GMAT & MBA community.

Overall, GMAT Club Forum is an excellent tool for anyone preparing for the GMAT. With its user-friendly interface and comprehensive features, it is an essential app for any GMAT aspirant who wants to ace the test and get into their dream business school.