DaFABRICATA is exactly correct. The only way to convert an L4 to an L1 is for about $120-$135, and you have to buy a body, tailcap and head! Seriously, though, if you buy a KX2 head from SureFire, you will essentially have a new E2L which uses the same optic as the L1 and has decent output and great regulated runtime (9 hrs).