An Authorization Definition Serial Number is a string value of arbitrary size for the Serial Number that is stored in association with this particular Authorization Definition.  

Normally this value is stored by the ClientProtector in the definition as a result of a successful Serial Number code exchange operation, however you can also programmatically get and set this value yourself.

This value is used by the ClientProtector during Serial Number operations such as an automated or manual code exchange with the CheckPoint License Server or during a Serial Number Check-In operation.

Each definition has its own Serial Number field, however, a Serial Number is not necessary for most operations on  Authorization Definitions - including Activation.   

More Information

For more information about Serial Numbers, see: Serial Numbers

For more information about using Serial Numbers with the CheckPoint License Server, see:  CheckPoint Central Server Controlled Licensing