.banneradsbox{
  max-width:920px; 
  margin: 10px auto 10px auto; 
  min-height:60px; 
  overflow:hidden; 
}

.banbox{
  margin:3px 9px 3px 9px; 
  max-width:438px; 
  max-height:56px;
  width: 95%;
  height: 95%;
  float:left;
  -webkit-border-radius: 4px;
  -moz-border-radius: 4px;
  border-radius: 4px; 
  border:1px solid #666;
  background-color: #fcfcfc;
}

.contenedor{
  margin:3px 9px 3px 9px; 
  max-width:438px; 
  max-height:56px;
  width: 95%;
  height: 95%;
  -webkit-border-radius: 4px;
  -moz-border-radius: 4px;
  border-radius: 4px;
  position: relative;
  display: inline-block;
  text-align: center;
}

.centrado{
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
}