diff --git a/README.md b/README.md
index c040dc7..2fdb026 100644
--- a/README.md
+++ b/README.md
@@ -17,7 +17,7 @@ HTML5 video provides a native API to accelerate playback of any video. The probl
 
 Once the extension is installed simply navigate to any page that offers HTML5 video ([example](http://www.youtube.com/watch?v=E9FxNzv1Tr8)), and you'll see a speed indicator in top left corner. Hover over the indicator to reveal the controls to accelerate, slowdown, or rewind the video (10 seconds + lowers playback speed). Or, even better, simply use your keyboard:
 
-* **a** - will rewind video 10s and lower playback speed.
+* **a** - will rewind video 10s and lower playback speed **by 10 points**.
 * **s** - will lower playback speed.
 * **d** - will accelerate playback speed.
 
diff --git a/inject.js b/inject.js
index 44bbf12..2ceceb7 100644
--- a/inject.js
+++ b/inject.js
@@ -85,10 +85,10 @@ chrome.extension.sendMessage({}, function(response) {
         videoTags.forEach(function(v) {
           if (!v.paused && !v.classList.contains("vc-cancelled")) {
             if (action === 'rewind') {
-              v.playbackRate -= 0.20;
+              v.playbackRate -= 0.10;
               v.currentTime -= 10;
             } else if (action === 'faster') { v.playbackRate += 0.10 }
-              else if (action === 'slower') { v.playbackRate -= 0.10 }
+              else if (action === 'slower') { v.playbackRate = Math.max(v.playbackRate - 0.10, 0.00) }
           }
         });
       }