According to Rule 1.10 in Senior League Baseball, the bat must meet certain specifications in terms of length, diameter, and weight. In this case, the bat is 34 inches long and 2-5/8 inches in diameter, which meets the requirements. However, it is only 25 ounces in weight, which is below the minimum weight allowed. Therefore, the defense is correct in claiming that the bat is illegal, and the umpire makes the batter get another bat. Hence, the answer is true.