diff --git a/classes/HighChart.php b/classes/HighChart.php
index 14fe17e..c4b3e88 100644
--- a/classes/HighChart.php
+++ b/classes/HighChart.php
@@ -20,6 +20,7 @@ abstract class HighChart {
 	// Default chart size.
 	protected $_height = '300';
 	protected $_width = '575'; 
+	protected $_ymetric = '';
 
 	// Colors to use for series
 	private $_series_colours = array('AAACCC','E0E0E0','CCC888','EEEBBB','666CCC','888888');
@@ -40,6 +41,8 @@ abstract class HighChart {
 				break;
 			case 'width': $this->_width = array_shift($args);
 				break;
+			case 'ymetric': $this->_ymetric = array_shift($args);
+				break;
 			default:
 				throw new Kohana_Exception('Unknown method :name',array(':name'=>$name));
 		}
diff --git a/classes/HighChart/Combo.php b/classes/HighChart/Combo.php
index 8d1a036..18969dc 100644
--- a/classes/HighChart/Combo.php
+++ b/classes/HighChart/Combo.php
@@ -91,7 +91,7 @@ $(document).ready(function() {
 		},
 		yAxis: {
 			title: {
-				text: 'MB'
+				text: '".$this->_ymetric."'
 			},
 			labels: {
 				formatter: function() {
@@ -102,7 +102,7 @@ $(document).ready(function() {
 		tooltip: {
 			formatter: function() {
 				var s;
-				s = '' + (this.point.name ? this.point.name+': ' : '') + this.y +' MB';
+				s = '' + (this.point.name ? this.point.name+': ' : '') + this.y +' ".$this->_ymetric."';
 				return s;
 			}
 		},