I don't think Aleph tubes will accept the 18650. I believe that Aleph tubes will accept 1 17mm diameter lithium ion, such as the 17670, but not the larger diameter 18650.
You might be refering to the tubes made by Tranquility Base which are Aleph or Surefire E-Series compatable tubes that will accept the 18650. I own a single 18650 model and it's first rate!
I hope this is helpful.