This host is a real looker!  For a single LED build, just add a 16mm MCPCB and 17mm driver.  

To build a triple LED flashlight, you will need to add the following components:

• 17mm Driver
  • If you are running more than a 3.4A driver, you must bypass the tailcap switch spring using either copper braid or thin 22AWG / 24AWG silicone wire.
• Triple LED
• Aluminum or Copper Spacer
  • You will have to drill and chamfer a small hole in the brass pill to allow the wires to pass through.
  • Aluminum is less expensive and lighter weight, while copper offers a small thermal advantage. 
• Carclo 105xx Optic
• Thermal Compound

This host works with protected cells, including the Protected NCR18650GA.

Specifications:

• Reflector Finish: Orange Peel
• Reverse-clicky Switch
• Uses 1x 18650 battery 
• Driver Diameter: 17mm
• MCPCB Diameter: 16mm
• Includes Lanyard
• Diameter: 24mm
• Length:  119mm
• Weight: 88g