There are two types of hardware / curtain rods that can be used when hanging lace curtains:

Tension Rod - used on the inside of the trim. A tension rod relies on pressure to hold the rod in place.

Projection Rod - this type of curtain rod projects outward from the window 1 1/4" to 3" depending upon the projection needed to clear other types of shades that may be hanging in the window.

All rods are adjustable to the correct length needed for your window.