Excellent apps!
An excellent application. In just a second, you can see which opening moves have been tried in a given position and their rate of success. You can also use the integrated chess program to suggest a move.
On more than one occasions, during the postmortem analysis of a tournament game, I was turning on my phone and with my opponent we checked the theory to see what we might have missed.
LeSwamp about
Chess Openings Pro, v4.1.1