Yes, it can be used in the daytime. The unit under complete darkness will be limited as these digital night vision devices require light. With the illuminator included I'd probably put it around 150 yards + or -, but it will depend again on the conditions of the night and how much light the unit has to work with.
Depends on size of target.....about 200 yards for hogs (longer if you add a larger ir illuminator) ..... yes it can be used in day . The front lens cover has pin hole for daytime use ....Its digital so daylight exposure doesn’t bother it