White outer ring for semi recessed pendant fire sprinklers.
Replace those missing rings. Have a spare ready.
These are a REQUIRED important part of a fire sprinkler.
They hold the sprinkler in place, and prevent heated air from
getting past, into the space above the ceilings.
These Tyco outer rings fit many Gem, Star, Tyco sprinklers
and can be just pushed on.
See images for list of models these will fit.