Beretta Mobilchoke 12ga Ported Ext. IM Choke Tube C6A865

Beretta MobilChoke Extended Ported 12 Gauge Choke Tube Improved Modified Black. How can I tell which choke tubes fit in my shotgun? Specifications for Beretta MobilChoke Extended Ported 12 Gauge Choke Tube: Manufacturer: Beretta Color: Black Fabric/Material: Steel Gauge: 12 Choke Tube System: Beretta/Benelli Mobil Gun Make: Beretta Package Contents: Beretta MobilChoke Extended Ported 12 Gauge Choke Tube Beretta C6A865: MobilChoke Extended Ported 12 Gauge Choke Tube Improved Modified Black