A concern with any holster revolves around retention. Most concealment holsters rely on the inherent tension between the body and the belt to hold the firearm snug, or the holster itself is molded to a specific firearm to keep things in place.
The Safariland ALS Paddle Holster approaches retention with the company's "ALS"—Automatic Locking System—series. A simple inward press with the strong hand thumb as the draw commences releases the locking mechanism that keeps the firearm secure otherwise. The ALS holster is IDPA approved and comes with a belt loop back that can be swapped for the paddle. A tension screw allows for adjustments that allow effortless draws (once the locking mechanism is disengaged, of course).
In use, the ALS takes a few tries to get used to, but once a small amount of practice has been made it becomes second nature. Attempts to remove the handgun from the holster by force or movement were completely unsuccessful. Should the wearer be so inclined (and capable), cartwheels would be unlikely to dislodge one's chosen firearm from the ALS holster.