... that to prevent fire,thanks. smoke alarm AK-218A4Description:1, Power:110VAC/220VAC/230VAC ... ) and 20-50 mA(alarm working)3,Sensitivity to smoke:In comply with UL217 &BS5446: Part 1 20004,Kite ... feet.6,Battery life: 3 year 7,Interconnecting Gas detector (1)Circuit for normally closed rely contacts (2)Circuit ... 30.6cm11,Quantity/BOX:80pcs12,CtnWei(kg):15kg13,Q`CTY/20`FT:33920pcs us electric smoke detector