I assume you mean tha CRIMSON TRACE LIGHTGUARD. I have one on my FS 9 along with the Crimson Trace Laser Grip. Both work very instinctively when you grip the gun, or you can decide which to use by how you squeeze the grip. You do not have to think about operating any switches. it has a manual off switch as does the laser if you wish to disengage it.
The light is plenty bright and fits on the gun like it was part of it, unlike bulky rail-mounted lights. It's very light weight does not affect the balance or aim; in fact, you hardly notice it's even there. Highly recommended.
