If the current auction price is $100 dollars and you place a maximum bid of $120 dollars, the system will bid $101 dollars on your behalf.
If no other participant places a bid, you win that auction lot for $101 dollars.
If another auction participant places a bid of $110 dollars, the system will subsequently place a bid of $111 dollars on your behalf. The system will continue to bid in $1.00 dollar increments until your maximum bid of $120 dollars is exceeded.
If another auction participant places a bid for $125 dollars, the auction lot price will display $121 dollars having exceeded your previously submitted maximum bid by $1.00 dollar.