Equipment and/or materials used in training, demonstrations, or teaching, which employ sight and sound simultaneously.

Any frequency of oscillation of a sound wave which is audible; usually in the range between 15 and 20,000 Hz

An audio listening device used to detect sounds of breaking and entering a building or a secure area within a

A mechanical fan, located in the attic space of a residence; usually moves large quantities of air at a relatively

Said of a doorway having jambs which are inclined slightly inwards, so that the opening is wider at the threshold

An open tank which is installed above the highest plumbing fixture in a building (e.g., in the attic) and which