Display available sizes on shop page

display_size_attribute_in_shop.php

<?php
/**
 * DO NOT copy the opening php tag
 * check if you're using the correct attribute slug
 */
add_action('woocommerce_after_shop_loop_item','display_size_attribute_in_shop');

function display_size_attribute_in_shop() {
    global $product;
	if( $product->is_type('variable') ){
	 
		$color_val = $product->get_attribute('pa_size'); 
		if( ! empty($color_val) ){
			 echo "<div class='size_att'>";
			 echo "<span>In sizes: </span>";
			 echo $color_val;
			 echo "</div";
		}
	 
    }
}