Astragals are used to cover the gap between leaves of doors in a pair. They can either be a spilt astragal which comes in two pieces, with one piece being installed on each leaf of the opening, when the doors are in a closed position, the astragal intertwines, closing the gap. This allows both leaves to operate independently. The other option is an overlapping astragal which is one piece fixed to one leaf of the opening. This allows only the active door to be opened first, and the use of a coordinator to ensure that the inactive door closes first allowing the active door to latch into it.

Coordinators are used on pairs of doors where both leaves can be opening, but one leaf must come to a full closed position so that the active leaf can latch into the inactive leaf, securing the opening.