rotation	Orientation of the handle.
position	Center of the handle in 3D space.
radius	Radius to modify.

Returns
float The modified radius

Note: Use HandleUtility.GetHandleSize where you might want to have constant screen-sized handles.

Make a Scene view radius handle.

RadiusHandle on the Scene View.

	// Simple script that draws and controls a float var on any Game Object that has the 
	// ColliderRadius.js script attached.
	
	@CustomEditor (ColliderRadius)
	class RadiusHandleJS extends Editor {
		function OnSceneGUI () {
	        target.areaOfEffect = Handles.RadiusHandle (Quaternion.identity, 
	        						target.transform.position, 
	        						target.areaOfEffect);
	        if (GUI.changed)
	            EditorUtility.SetDirty (target);
	    }
	}

And the Script attached to this handle:

	// Place this script where you want to see the RadiusHandler working on.
	
	var areaOfEffect : float = 1;