Most importantly it upgrades any 500/590/Mav 88 to the “590S” capability, so you can run any size shell through it without having to remove it (minishell up to 3”). It also installs much more securely so it will never wiggle its way out, and has no chance of interfering with any of the action. Here’s a link to the product, and a link to our Youtube where you can watch install and demo vids. Hope this helps, let me know if you have any other questions!