woocommerce_get_availability_class │ filter-hook │ WC 1.0

Usage

add_filter( 'woocommerce_get_availability_class', 'wp_kama_woocommerce_get_availability_class_filter', 10, 2 );

/**
 * Function for `woocommerce_get_availability_class` filter-hook.
 * 
 * @param  $class 
 * @param  $that  
 *
 * @return 
 */
function wp_kama_woocommerce_get_availability_class_filter( $class, $that ){

	// filter...
	return $class;
}

$class

-

$that

-

Where the hook is called

return apply_filters( 'woocommerce_get_availability_class', $class, $this );

Where the hook is used in WooCommerce