A popular and effective way to improve the performance of your shotgun. Minimum gap geometry and high resolution RMS interior finishes gives less pellet deformation; consistently tighter patterns. Choke constriction is laser marked, on color-coded band so there is no need to remove choke to verify size. Long tube with hidden wrench slots extends beyond the length of the muzzle. Knurled grasping band speeds installation and removal. Helical rifled Diffusion spreader tubes provide a pattern that is more open than cylinder. It is not recommended to shoot Federal's Black Cloud or any of their ammunition that utilizes their Flight Control Wad in ported chokes due to interference with its performance. Extends 3/4" to 1" Beyond the Muzzle, Depending on Shotgun Brand.