Adjusting size of a halo in C#

Hi there folks.

Currently working on a scene with some streetlights. These lights have two components- a halo component, and a script. I want to use that script to adjust the radius of the halo, so that we have a sort of flickering effect.

Currently going with-

 void Update() 
 {
     float FlickRandom = Mathf.PingPong (1f, 2f);
     gameObject.GetComponent ("Halo").size = FlickRandom;
 }

Although it does not seem to be able to find a definition for 'size'. Is there a different way I need to describe the radius for it?