Carlson's Choke Tubes 20 Gauge Shotgun Snap Caps Set of 2. The striking area on this Shooting Accessory made by Carlson's Choke Tubes is spring loaded to help cushion and protect firing pins. The 12 & 20 Gauge Shotgun Snap Cap by Carlson's Choke Tubes makes an excellent tool for teaching and reducing flinching. Features of Carlson's Choke Tube 12 and 20 Gauge Shotgun Snap Caps: Protects firing pins Perfect tool for beginners Spring loaded striking area Package Contents: Carlson's Choke Tubes 12 and 20 Gauge Shotgun Snap Caps Carlson's Choke Tubes 20 Gauge Shotgun Snap Caps Set of 2 00098