Kit includes special Crown barrel for shooting Arrows, plus 4 arrows. Extra arrow can be had by the 6 pack.
https://spaweapons.com/collections/fx-accessories/products/fx-crown-arrow-barrel-kit-taking-orders-for-9-18-delivery
https://spaweapons.com/collections/fx-accessories/products/fx-crown-arrow-barrel-kit-taking-orders-for-9-18-delivery