Simplex 4903-9418 Category : Simplex The lack of TrueAlert branding on the front of the alarm, as well as the odd grille, are signs that this is an early version of the TrueAlert. Brand SimplexModel 4903-9481Manufacturer SimplexType Alarm (Speaker/Strobe, 4-Wire)
Edwards 276B-1320 Category : EST/EdwardsThis is essentially the single-action, non-addressable version of the EST SIGA-278.
Simplex 4903-9101 Category : SimplexSince this is a ceiling-mount unit, it’s model number is probably different from 4903-9101, but I couldn’t figure out what...
