Invulnerable Save x+

Each time a shooting attack is made against an operative, the defender can use its invulnerable save instead of its normal Save characteristic. An invulnerable save is used like a normal Save characteristic, except that it cannot be modified in any way, and is not affected by any APx special rules (meaning the defender would use their normal Defence characteristic). x of the invulnerable save is the dice roll required for the defence dice to be successful, e.g. 4+.