Conventional rail clips will not work on the back side of the HP P4515 family of cartridges since there is no ledge for the clips to snap onto. Static Control offers an adhesive rail clip to secure the split sections of the cartridge. The peel and stick, pressure sensitive adhesive holds securely to prevent toner leakage and resulting print defects. Three locking rails (CSUNIV-500) are required for the front side of the cartridge.