For safety training, function testing or safely de-cocking without damaging the firing pin, A-Zoom 40S&W Snap Cap training rounds are much more than conventional snap- caps. They are precision CNC machined from solid aluminum to precise cartridge dimensions, then hard anodized for ultra-smooth functioning and long life. These snap caps offer shooters an affordable option to train in the home without putting holes in their walls. The A-Zoom 40S&W Snap Cap is also perfect for simulating malfunctions while shooting. These are a great accessory to keep in your range bag at all time.