IPhone How to Open.syncdb

Hi guys,

I Reset my IPhone 4 for Simlock Because my Contract is Finish with at&t. before i do this i creat a back but after reset itune ask to restore from old back or setup a new iphone i click on new 😟 .unfortunately Itunes overwrite my backup .None of my contacts were saved to my sim card but i've found a backup file on my pc which should have them in (C:\AppData\Roaming\Apple Computer\SyncServices\Local\TFSM\com.apple.Contacts)

The problem I'm having is it's a ".SYNCDB file" and I have no idea what programme to use to open it. Can anyone help?