Features:
1) Models: 2-wire, 4-wire  with UL268/521 and EN54-5/7 certificate
2) Advanced detection and discrimination algorithms
3) Easy installation and maintenance
4) Polished low-profile housing design
5) Durable sensor head, no need for replacement
6) SMD circuit board design: satisfactory quality and reliability guaranteed
7) Integrated heat detector for SD-119-2H and SD-119-4H models
8) N/C (normal / close) and N/O (normal / open) relay output ways for option
9) AR (auto reset) function for security systems (optional for 4-wire models)
10) Sensor base: standard and Schottky diode style for option
11) Five-year warranty