The cop tops are for immediate point and shoot spray with no safety, which makes sense in some situations.  Nevertheless, we are a big proponent of the flip tops because of the flip up safety feature, which reduces the chance of accidentally firing.  With the flip tops you have to insert your finger and flip the top up in order to fire the unit.  Also, the fog spray generally works best for civilian use as they due not require pin point accuracy.  These units also contain the UV dye that can be seen under police ultra violet lights.