Sorry, familiarity breeds complacence. As was said before, the lever in the middle of the trigger is a block. It must be depressed before the trigger can be pulled to fire the gun. If the side of the trigger rubs a pocket or holster as it is recovered into either, the gun cannot fire.
The caliber is 40 S&W, the standard Law Enforcement round. It has about the same power as most 45 Auto ammo. It has a high level of performance in a small frame, making it suitable for folks with average sized hands, and is lighter to carry. The gun also holds a lot of powerful ammo, 14 rounds, for its size.
The Glock 23 is arguably the Gold Standard of those who prefer an autoloader for concealed or discrete carry.
$399 shipped.