<?php
if ( wp_is_mobile() ) { // If it is a mobile device

get_template_part( 'mobile-front', 'page' );

} else { // If it is not a mobile device

get_template_part( 'desktop-front', 'page' );

} // end wp_is_mobile()

<?php
if ( wp_is_mobile() ) { // If it is a mobile device

get_header( 'mobile' );
// Display some other stuff here
get_footer( 'mobile' );

} else { // If it is not a mobile device

get_header();
// Display some other stuff here
get_footer();

} // end wp_is_mobile()