I had taken the 507k X2 off of my XD-E 3.3 (a 9mm version) to put on my lighter (much lighter) FN Reflex. It didn't mean I didn't want to carry the XD-E from time to time, however, it is a chunk. A lovely, blocky, tall slided chunk. My new Sig Romeo Zero "ELITE!!!!!" is now residing on my XD-E...