The Reliable Model F3 Standard Response Dry Horizontal Sidewall Sprinkler is a thermosensitive glass-bulb spray sprinkler for use in areas subject to freezing. The sprinklers are designed for dry systems and preaction systems where it is necessary to prevent water or condensation from entering the drop nipple before sprinkler operation. They may also be installed in spaces subject to freezing and supplied from a wet system in an adjacent heated area. See Technical Data Sheet for further information.