Gray has square threads, silver and orange has trapezoidal threads.
A short body tube for Convoy S2+ flashlights which will allow the use of 18350 batteries.
Important: It has been brought to my attention that these tubes are not exactly the same internal diameter at the original 18650 tube. This means some (if not all) protected 18350s, or anything with a thick wrapper may not fit. Unfortunately there is nothing I can do about this, that's just how Convoy makes them.