Carlson's Delta Waterfowl Choke Tubes are designed out of 17-4 stainless steel for all-weather durability and come in a three pack that includes a close range, medium range, and long range choke. It's also packaged with a choke case that makes carrying it to the duck blind easy and convenient. The Delta Waterfowl choke tube set all have a 25% longer parallel section which helps deliver more consistent patterns over conventional chokes. Each choke tube has the choke size and constriction marked on the end of the choke for easy reference in the field.