diff --git a/debian/changelog b/debian/changelog
index 8f84a4d..5c3ece9 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -1,6 +1,7 @@
 raspi-config (20170712) UNRELEASED; urgency=medium
 
   * Add pi model as backtitle
+  * Define memory split units
 
  -- Serge Schneider <serge@raspberrypi.org>  Tue, 11 Jul 2017 12:20:26 +0100
 
diff --git a/raspi-config b/raspi-config
index 4d9ba60..ed14011 100755
--- a/raspi-config
+++ b/raspi-config
@@ -414,7 +414,7 @@ do_memory_split() { # Memory Split
     [ -z "$CUR_GPU_MEM" ] || [ $CUR_GPU_MEM = "0" ] && CUR_GPU_MEM=64
     ## ask users what gpu_mem they want
     if [ "$INTERACTIVE" = True ]; then
-      NEW_GPU_MEM=$(whiptail --inputbox "How much memory should the GPU have?  e.g. 16/32/64/128/256" \
+      NEW_GPU_MEM=$(whiptail --inputbox "How much memory (MB) should the GPU have?  e.g. 16/32/64/128/256" \
         20 70 -- "$CUR_GPU_MEM" 3>&1 1>&2 2>&3)
     else
       NEW_GPU_MEM=$1