Characteristic overwrite template

-- HikaShop version -- : 2.4.0

Hello.
In the product/show_block_characteristic.php page of hika shop, in the top there is the following code:

if($this->params->get('characteristic_display') != 'list') {
	echo $this->characteristic->displayFE($this->element, $this->params) . '</div>';
	return;
}

i really appreciate your answer.
I have followed the hard way (create a hikashop_characteristics.php inside template/html folder) because I need to add some css clases inside each input field.
Thank you very much