A kind of bottled beverage produced by a beverage company is printed with "600 ± 30ml" on the outer package. What is the meaning of "± 30ml"? Expression

A kind of bottled beverage produced by a beverage company is printed with "600 ± 30ml" on the outer package. What is the meaning of "± 30ml"? Expression

"± 30ml" is the error range of bottled beverage. The maximum is 630ml and the minimum is 570ml
They are all qualified and within the allowable error range