Double Door Astragal
An astragal is used to fill the gap between double doors.
An astragal should not be confused with a mullion, which sits between or behind the meeting stiles of a pair of doors (we will ask later about mullions which are dependent on hardware being used)
In order for an astragal to function properly, it should be installed on either:
the pull side of the active leaf
the push side of the inactive leaf.