These units require a fire alarm/smoke alarm system to function.
They are not standalone units.
System Sensor 2WTA-B i3 Series 2-wire, Photoelectric i3 Smoke Detector
Specifications
Alarm Current:
130mA max., limited by panel
Detection
Photoelectric
Dimensions
2.0″ (51mm) H x 5.3″ (127mm) Dia.
Freeze Trouble
41°F (5°C)
Heat Sensor
135°F (57.2°C) fixed
Humidity Range
0% to 95% RH, noncondensing
Maximum Ripple Voltage
30% of applied voltage (peak to peak)
Operating Voltage
12/24 V non-polarized nominal, 8.5 min. to 35 max.
Sensitivity
2.5%/ft. nominal
Sounder
85 dBA
Standby Current
50 µA max. avg., 100 µA peak
Temperature Range
32° to 100°F (0° to 37.8°C)
Weight
7.1 oz. (200 g)
Wiring
2-wire
Wiring Gauge
14-22 AWG
Features:
System Sensor i3
series smoke detectors represent significant
advancement in conventional smoke detection. The i3
family is
founded on three principles: installation ease, intelligence, and
instant inspection.
Plug-in detector line, mounting base included
Large wire entry port –  In-line terminals with SEMS screws
Mounts to octagonal and single-gang back boxes,
4-square back boxes, or direct to wall or ceiling
Stop-Drop N Lock attachment to base
Removable detector cover and chamber
Built-in remote maintenance signaling
Drift compensation and smoothing algorithms
Simplified sensitivity measurement
Wide-angle, dual-color LED indication
Loop testing via EZ Walk feature
Built-in test switch
i3
Series Detectors:
2W-B 2-wire Standard i3 Detector
2WT-B 2-wire Standard i3 Detector with Fixed 135° Thermal Sensor
2WTA-B 2-wire i3
Detector with Fixed 135° Thermal Sensor and Sounder
4W-B 4-wire Standard i3
Detector
4WT-B 4-wire Standard i3
Detector with Fixed 135° Thermal Sensor
4WTA-B 4-wire i3
Detector with Fixed 135° Thermal Sensor and Sounder