???? ???? ????? ???????? ???? ??????? ??????? ????????? ???????? ???? ????? ??? ?????? ??????? ??????? ?? ?? ???????? ????????? ??????? ?????? ??? ??????? ???? ????? ???.????? ??? ?????: ????????? ????? ????? ?? ?????? ??????????? ?????? ??????? ?? ???? ????? ??? ??????? ? ????? ??? ????? .Battery-operated detectors are simple to put in, normally n