FOR YOUR CONSIDERATION IS THIS NEW UNUSED BALLISTIC KNIFE SPRING. I HAVE 3 OF THEM AND AM LETTING THIS ONE GO. IF YOU HAPPEN TO HAVE A BALLISTIC KNIFE AND NO SPRING, NOW IS YOUR CHANCE TO GET THIS ONE FOR YOUR COLLECTABLE KNIFE. A SPRINGLESS BALLISTIC KNIFE IS NOT VERY BALLISTIC WITHOUT THIS SPRING. I AM IN NO WAY INCOURAGING YOU TO ACTUALLY PUT THE SPRING INTO YOUR KNIFE. THIS IS BEING SOLD ONLY FOR THE PURPOSE OF HAVING A COMPLETE UNASSEMBLED KIT. THIS IS A TUFF ONE TO FIND ,GET IT WHILE YOU CAN. THANKS FOR LOOKING! GOOD LUCK BIDDING.this spring is a heavy stainless steel upgraded spring measuring aprox.10 inches. spring has the closed end loop for the screw to fit and be mounted to the bottom of tube so it does not fly out with the blades tube when triggered. these are very hard to find and rarely given up when found. I was able to get these springs when I bought a bunch of these knives from a dealer and been hoarding them for many years. get them while they last.