loa

http://www.google.com.vn/imgres?q=loa&hl=vi&client=firefox-a&sa=X&rls=org.mozilla:en-US:official&channel=s&biw=1366&bih=601&addh=36&tbs=isch:1&tbnid=5nNSak8jZ-2d1M:&imgrefurl=http://chodientu.vn/mua-ban/1900/Loa-va-he-thong-loa.html&imgurl=http://static90.ichodientuvn.com/pict/items_m/item.09_2009/large_09_2009_1253689337216607.gif&ei=KsxtTfr9McvIcZ_u6b0F&zoom=1&w=140&h=118&chk=sbg&iact=hc&vpx=294&vpy=166&dur=40&hovh=94&hovw=112&tx=147&ty=61&oei=3MptTeDXMYbXcLu4pMMF&page=84&tbnh=94&tbnw=112&start=933&ndsp=9&ved=1t:429,r:1,s:933