Totals bets, or over/under bets, are a type of bet where the bettor decides whether some game statistic will be over or under a specified strike.
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One very common example is a bet on whether there will be Over 2.5 or Under 2.5 bets in a Best of 3 series. In this case, we could have said the totals bet is on the number of maps played with strike of 2.5.

Bettors generally favour the Over 2.5 Maps when the teams are evenly matched, and Under 2.5 Maps in big favourite / underdog match ups. 

There are also many totals bets that look at esport specific in game metrics.
In Counter-Strike, a common example is whether a map will have over or under 26.5 rounds. 

Similarly to the Total Maps bet, bettors favour the Over 26.5 Rounds when teams are evenly matched since it is more likely to be a close game. When there is a strong favourite, the game is more likely to be lopsided and end early, making the Under 26.5 Rounds more attractive.
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