function spinna360_nof($noi) {

woocommerce_wp_select(
    array(
        'id'        => '_select_noi',
        'label'     => __( 'Select number of images: ', 'spinna360' ),
        'selected'  => true,
        'value'     =>  $noi,
        'options'   => [
            '24'        => __( '24', 'spinna360' ),
            '36'        => __( '36', 'spinna360' ),
            '48'        => __( '48', 'spinna360' )
            ]
        )
    );
}