NEWS YOU CAN USE: What Is the Striker Control Device? “Any number of items could conceivably find their way into the holster right around the time you’re putting your firearm away. It’s rare, yes, but it can happen. With the SCD, you holster with your strong-hand thumb on the back of the slide, over the SCD. If the trigger were to catch, initiating a pull, you’ll feel the SCD moving (or, trying to move) under your thumb. Full stop, that’s all the SCD does.”