3x 8kg Upgrade Springs for Nerf Hammershot, Sweet Revenge, and Lawbringer Set of three (3) 8kg custom fitted upgrade springs. Compatible with Nerf Hammershot, Sweet Revenge, and Lawbringer. Mod at your own risk! Increasing the spring tension can break or damage stock internal components of your blaster. Some blasters are extremely hard to reassemble, and we won't be able to troubleshoot problems due to user error. Blaster not included.