How to adjust height of the selectpicker dropdown

I corrected it by myself...

Just add data-size in the html

<select class="selectpicker" data-dropup-auto="false" data-size="5" id="estType" name="estType">
   <option selected disabled value="0">Select</option>'
</select>

Using Bootstrap Select, data-size doesn't work for me. I need to override CSS with this:

div.dropdown-menu.open{
  max-height: 314px !important;
  overflow: hidden;
}
ul.dropdown-menu.inner{
  max-height: 260px !important;
  overflow-y: auto;
}

Change the size as you like.