The Vertebrae T3 bolt shroud is made to work perfectly with most T3 bolts. However, due to some slight variations in bolt size, it might be a loose fit on some bolts. There is an easy solution for this: Please open a BIC or similar pen, and remove the spring. Cut the spring in two, and place the half spring in the bolt shroud before entering it on the bolt. The bolt shroud should now be a tight fit on the bolt.