Thanks, Trout. The OAL is 3.75". The light was put together over a span of a year, starting with the KL4 head. I supplied the head and McGizmo charged me around $75 for parts and labor, shipping included. The Aleph II 1x123 body cost around $25 from John Crighton (jcciv in Candlepowerforums.com and eBay). The E2D tailcap cost $40, also from John. I sent the tailcap to McGizmo to have it stripped and replated. Cost was $20, priority mail shipping included. Total cost= ~$160 (spread out in a year). Note: If the head is substituted for a new generation KL1, it comes out cheaper.