Can you explain the rules of the card game where players start with 4 cards face down and are allowed to look at 2 of them?

In the card game where players start with 4 cards face down and can look at 2 of them, the objective is to have the best hand possible. Players can choose which 2 cards to look at, but must keep the other 2 face down. The game typically involves betting and bluffing to try and win the round.