This stainless steel pocket clip can be adapted to many flashlights with a little drilling and bending, but it specifically fits many of the single 18650 tube lights such as the Convoy S2 and S6.  

Center to center measurement:  ~6.5mm
Length:  ~62mm

Includes:

• Stainless Steel Clip
• Philips Head Screws and Nuts
• No Longer Include Allen Head Wrench (no longer needed)