diff --git a/inc/extras.php b/inc/extras.php
index 51ec124..f9c09dc 100644
--- a/inc/extras.php
+++ b/inc/extras.php
@@ -98,10 +98,10 @@ if ( ! function_exists( 'understrap_post_nav' ) ) :
 						<?php
 
 							if ( get_previous_post_link() ) {
-								previous_post_link( '<span class="nav-previous float-xs-left">%link</span>', _x( '<i class="fa fa-angle-left"></i>&nbsp;%title', 'Previous post link', 'understrap' ) );
+								previous_post_link( '<span class="nav-previous float-sm-left">%link</span>', _x( '<i class="fa fa-angle-left"></i>&nbsp;%title', 'Previous post link', 'understrap' ) );
 							}
 							if ( get_next_post_link() ) {
-								next_post_link( '<span class="nav-next float-xs-right">%link</span>',     _x( '%title&nbsp;<i class="fa fa-angle-right"></i>', 'Next post link', 'understrap' ) );
+								next_post_link( '<span class="nav-next float-sm-right">%link</span>',     _x( '%title&nbsp;<i class="fa fa-angle-right"></i>', 'Next post link', 'understrap' ) );
 							}
 						?>
 					</div><!-- .nav-links -->