I need to manipulate a string value by inserting a '-' character into the string. I have two different string formats: one is made from numbers only and always eight digits long. I need to insert the character after the first 4 digits. The other one starts allways with 2 letters and can be between 4 and 16 characters long and I need to insert the - after the first 2 characters. Any help would be appreciated. Thanks.