I have a
Lasermax on my Glock 22. It replaces the guiderod, so the laser is housed internally. The laser is activated by a switch (depending on which weapon it is installed on - for the Glock, the slide lock [take-down lever] is used to activate the weapon.)
Crimson Trace is the other popular laser. However the laser is mounted on a set of rubber grips. The grips contain a pressure sensitive pad that activates the laser when you assume your normal grip on the weapon.
However neither Lasermax or CT has a model for your particular handgun. If you have a rail, then you could use something like the
Lasermax rail-mounted laser, which is fairly low profile.
I also have a
Streamlight TLR-2 that is a real nice unit. I wrote an off-the-cuff
review of it awhile back.
There are lots of divided opinions regarding lasers. Most people who see utility in them use them for training purposes (you can really see how much you flinch and how unsteady your are with a laser).
I think they are good to have, but not a necessity. Good ones are costly though. I doubt you will spend less than $100 for a quality piece.
Hope this helps. Good luck on your purchase.