First Alert smoke detector/alarm cover

When I bought my house, it had two hardwired smoke alarm mounts installed in each bedroom (I think to allow for separate CO2 and smoke alarms). I recently replaced all my alarms with 2-in-1 units, so each room had an extra, unused smoke alarm mount in the ceiling.

This cover slides in to the existing ceiling mount and covers the hole and exposed wires.

The fit isn't super satisfying - it's a little loose - but since it's in the ceiling and won't be bumped, I didn't bother making a tighter-fitting version.

This mount was designed for a First Alert brand smoke detector mount, although it might work for other brands as well.