What a keystone round is
This is a round gable vent with molded keystones on the frame. The circle is the same idea as a plain round. The keystones, set at the cardinal points, make it more formal and more classical. It is trim and vent together.
The piece is molded high-density polyurethane, factory-primed white, and ready for paint. It does not rot, and it cuts and fastens much like wood trim. Paint will catch on the keystone edges, so a careful brush or spray matters more here than on a plain circle.
Where it looks right
Use it on a house that already has keystones: a door head, a window, a pediment, or a porch entablature. Dropped onto a plain farmhouse with no other classical detail, the keystones can look stuck on. Center it under the peak the same way you would center a plain round.
The top keystone should point at the ridge. If the vent is rotated, one keystone leans and the whole circle looks unfinished.
Open or closed
open round gable vents with keystones ventilate through the slats. closed round gable vents with keystones are decorative only. The keystones do not change that. Choose open when the circle is part of the attic plan, and closed when you want the formal face on a wall that should stay sealed. The open versus closed page spells out the practical difference.
A short sizing note
LORK16, a 16 inch round gable vent with keystones is a 16 inch round, close in size to a plain 16 inch round, with extra frame depth from the keystones. Include the keystones when you measure clear space to the rake. The sizing page suggests a visual width of about one fifth to one quarter of the gable, for appearance only.
Pair it with
Pair it with the keystone that is already over the front door, and with a round or oval window if you have one. Skip it if the rest of the gable trim is flat and square. A plain round is the quieter partner for that house. The install overview covers adhesive, fasteners, and paint.