"2X" means that the second team (athlete, guest team) will win or draw. 2X in bets on the decisive match of the Champions League is estimated at 2.02. "12" is means that team 1 or team 2 will win the match.
In Double Chance Betting, you select two possible outcomes out of three (or more at special bet types) possible scenarios: in a soccer game either Team A wins or draws (1X), Team B wins or draws (X2), or either Team A or Team B wins (12).
Under 2.5 Bets win if there are 0, 1 or 2 goals scored in the match. Bets lose if there are three or more goals scored in the match. Under 2.75 Bets win if there are 0, 1 or 2 goals scored in the match. If there are three goals exactly, half the stake will be returned and half will be lost.
Specifically, the bettor can choose two of the three possible outcomes, either Home Win and Draw (1X), Away Win and Draw (2X), or Home Win and Away Win (12).