Belt light, a belt that has a flashlight. you can wear it and turn it to on/off
Gun light you just strap it over or under you gun's barrel, being able to turn it on/off and attaching/removing to the gun.
head light similar to the belt one but this is worn in a strap over your head or helmet, just like those guys that go into caves do.
with those you can have both hands free to drag a corpse, fight big bad mofos and whatever under dark situations.