SC-2003A-308 is a photoelectric smoke alarm, it accords with ISO/DIS 12239 standard.It has much effect to detect smoke. It is stand alone model. Specification:Power source: DV9VStatic current: 85db(3m)Low voltage alarm:6.8v~7.2vWorking temperature:-5~+ 40Working humidity: < 93%RH Features: 1) Electric voltage: DC 9 to 15V, connect with the major machine 2) Electric current: static state electric current bellow then 50 As 3) Electric current bellow than 15mAs 4) Working environment: temperature 10 to 50 C, relative humidity bellow 97%5) Watch area: 60sqm 6) Outer shell: ABS 7) Size: 10 x 450mm 8) Remarks: GB4715-1993 producing area:China payment:T/T, L/C supplying capacity:12,000pcs/day