private function getUrlTemplate()
    {
        $filter = $this->getFilter();
        $item   = current($this->getFilter()->getItems());

        $regexp      = "/({$filter->getRequestVar()})=(-?[0-9]+)/";
        $replacement = '${1}=<%- from %>-<%- to %>';

        return preg_replace($regexp, $replacement, $item->getUrl());
    }