HEVI-Choke Turkey are available in 12 and 20 gauge, in ported and non-ported versions, HEVI-Choke choke tubes help you squeeze every bit of performance from your HEVI-Shot ammunition. *WARNING: Extreme range choke tubes are not recommended for steel pellets larger than BB or excessive speed of more than 1550 fps. Use mid-range choke tube for those applications. Compatible with Mossberg (835,935).