{set $custom_attribute_classes = $custom_attribute_classes|append( 'input_noborder' )}
<input type="checkbox" class="{$custom_attribute_classes|implode(' ')}" name="{$custom_attribute}" id="{$custom_attribute_id}_source" value="{$custom_attribute_default|wash}"{if $custom_attribute_disabled} disabled="disabled"{/if} title="{$custom_attribute_title|wash}" />