"Medical diagnostic tool that allows you to see the health of friendly and enemy players when using the scope."The Bio-Scanner is a scope that when attached allows you to see health bars floating above a players head. It has a relatively large range. It will also turn the screen into a faded green.
The Bio-Scanner is best used on a healing weapon, or a ranged weapon. It can be used to pick off weak enemies at a distance (such as with a sniper) or to prioritize healing. Its a useful tool and has the same stats as the iron sights.