Vista System Volume Information

I need to understand the GUID of the VSS

the second GUID is always the same, even on the example I found on the net

{eec72f9f-b2b8-11dd-9261-001636f3014f}{3808876b-c176-4e48-b7ae-04046e6cc752}

can someone help me to resolve the two guid to the service or device ?

Thanks