Secure Lock The newly patented Secure Lock nipple of Sapim is a locking mechanism that prevents nipples from untightening. The advantages of this easy locking system are: - Can be used on truing machine - No loose function while truing the wheel - Available on most current Sapim nipples - Easy to recognize - Highly precise and accurate machines have specifically been developed to produce this type of locking system. - They ensure stable and well defined deformation on the thread