diff --git a/src/_bootstrap3.breakpoints.scss b/src/_bootstrap3.breakpoints.scss
index 9b8e5cc..5712477 100644
--- a/src/_bootstrap3.breakpoints.scss
+++ b/src/_bootstrap3.breakpoints.scss
@@ -1,9 +1,9 @@
-$screen-xs-max: 767px;
+$screen-xs-max: 767px !default;
 
-$screen-sm-min: $screen-xs-max+1;
-$screen-sm-max: 991px;
+$screen-sm-min: $screen-xs-max+1 !default;
+$screen-sm-max: 991px !default;
 
-$screen-md-min: $screen-sm-max+1;
-$screen-md-max: 1199px;
+$screen-md-min: $screen-sm-max+1 !default;
+$screen-md-max: 1199px !default;
 
-$screen-lg-min: $screen-md-max+1;
\ No newline at end of file
+$screen-lg-min: $screen-md-max+1 !default;
\ No newline at end of file
diff --git a/src/_bootstrap4.breakpoints.scss b/src/_bootstrap4.breakpoints.scss
index 7e6b55c..e22935f 100644
--- a/src/_bootstrap4.breakpoints.scss
+++ b/src/_bootstrap4.breakpoints.scss
@@ -1,9 +1,9 @@
-$screen-xs-max: 33.9em;
+$screen-xs-max: 33.9em !default;
 
-$screen-sm-min: 34em;
-$screen-sm-max: 47.9em;
+$screen-sm-min: 34em !default;
+$screen-sm-max: 47.9em !default;
 
-$screen-md-min: 48em;
-$screen-md-max: 61.9em;
+$screen-md-min: 48em !default;
+$screen-md-max: 61.9em !default;
 
-$screen-lg-min: 62em;
\ No newline at end of file
+$screen-lg-min: 62em !default;
\ No newline at end of file