You can specify values between 0 and 99. You can specify multiple values (for example, "0,1") or a range of values (for example, "0-5"). The default value is 12.
For Application Load Balancers, you can specify values between 200 and 499, with the default value being 200. You can specify multiple values (for example, "200,202") or a range of values (for example, "200-299").