You’re able to quickly size up an opponent’s combat capabilities. Choose a target you can accurately perceive and have the GM make a secret Insight check for you as a free action, opposed by the target’s Deception check result.
If you win, the GM tells you the target’s attack and defense bonuses relative to yours (lower, higher, or equal). With each additional degree of success, you learn one of the target’s bonuses exactly. If you lose the opposed roll, you don’t find out anything. With more than one degree of failure, the GM may lie or otherwise exaggerate the target’s bonuses.
D20 Hero SRD Advantages Article-http://www.d20herosrd.com/5-advantages