tax_query
$tax_query = array( 'relation' => 'OR', array( 'taxonomy' => 'pa_rozmiar-felg', 'terms' => array( '15', '16', '17', '18' ), 'field' => 'slug', 'operator' => 'IN', 'include_children' => true, ), );
$tax_query = array( 'relation' => 'OR', array( 'taxonomy' => 'pa_rozmiar-felg', 'terms' => array( '15', '16', '17', '18' ), 'field' => 'slug', 'operator' => 'IN', 'include_children' => true, ), );