accepts

An Element, jQuery element, a selector or a function identifying which Draggable elements the Droppable should work with.
Defaults to "*", which means that all kinds of Droppable elements are accepted.

<div id="div2" style="width:100px; height:100px; border:1px solid black;">
    Drop items here...
</div>

<script type="text/javascript">
    jQuery(function ($) {
        $("#div2").shieldDroppable({
            // accept DIV elements having "mycls" as a class
            accepts: "div.mycls" 
        });
    });
</script>

The following example shows how to use a function to determine if a Draggable will be accepted.

<script type="text/javascript">
    jQuery(function ($) {
        $("#div2").shieldDroppable({
            // accept DIV elements having "mycls" as a class
            accepts: function(draggable) {
                return $(draggable).hasClass("can-drag");
            }
        });
    });
</script>