Rank 1
Your Counterspell also Silences the target for 2 sec.
Improved Counterspell
Client records describe this reading. They do not confirm availability in gameplay.
Current client record
Rank 2
Your Counterspell also Silences the target for 4 sec.
Sourced change history
No changes in the tracked log could be matched to this record. This does not mean the ability or item has never changed.