? ?.?. ??? ??????? ?? ????????? ??? ?????????? ??? ???? ??? ??????. ???????? ??? ?? ???? ??? ??????????? ????? ??????????; ???????????? ?? ??????? ??? ?? ???????? ???????? ???? ?????????? ??? ???? ????? ??? ???? ??? ????? ??????.Dust, sweat and drinking water resistance will not be long term circumstances and resistance may decrease as a result of