My new tacticool Tri-Strike, semi safe for the outside use. 4.5kg spring, new catch and dart tooth spring (after I lost both when the insides blown into my face during the dissassembly),
9KG Upgrade Spring for Nerf Modulus Tri-Strike Toy | Worker Nerf Mods - Workermod.com
Nerf MEGA Tri Break 7KG Modification Upgrade Spring Coil - Etsy