The PX4 Storm SD (Special Duty) is a US-civilian-market variant of the PX4 Special Duty platform, featuring a threaded barrel in .45 ACP for suppressor mounting, full-length Picatinny rail, and ambidextrous controls. Distinguished from the standard Special Duty by market-specific packaging and minor finish differences. Discontinued in favor of consolidation with the Special Duty line. Type: Semi-Auto Pistol Action: Double-Action/Single-Action Caliber: .45 ACP Capacity: 9 Year introduced: 2008, Italy Weight: 31 oz Overall length: 8.05" Status: Discontinued Intended use: defense, duty