The right tackle in football is the player in the offensive line that when positioned on the line of scrimmage stays on the right side of the right guard. The left tackle is on the other side of the line of scrimmage. They play the same position as the right tackle, only on the other side. Both the right and left tackle positions are sometimes referred to as Offensive Tackles, or simply tackles. The tackles are generally the biggest and strongest players on a football team. Their job is to block any defensive players who are trying to get to the quarterback or to stop a running play.
The left and right tackles' jobs are different depending on what is the quarterback's blind side. Since the blind side is usually the left, right tackles will generally face the opponent's best run-stopper. A good right tackle must combine strength with athleticism, and also having good technical skills such as footwork and play reading.