How to set default value in type radio

I did add this code but not working, please help…

$meta_boxes[] = array(
		'title'  => __( 'Radio Field Demo', 'your-prefix' ),
		'fields' => array(
			array(
				'name'    => __( 'Radio', 'your-prefix' ),
				'id'      => 'radio',
				'type'    => 'radio',
				'std'    => 'value1',
				'options' => array(
					'value1' => __( 'Label1', 'your-prefix' ),
					'value2' => __( 'Label2', 'your-prefix' ),
				),
			),
		)
	);

https://www.ads-software.com/plugins/meta-box/