Wagering requirement — the calculation
The multiplier determines how much you must wager before you can withdraw. A 500₪ bonus with x40 = a 20,000₪ turnover. If the game's house edge is 4%, the expected loss over that turnover is about 800₪ — meaning the bonus has negative expected value.
Check whether the multiplier applies to the bonus alone or to bonus + deposit — the difference doubles the requirement.