Thanks. I just checked my sofirn sc31b &sp31. Both came with button top but do have a spring up top and do run with my flat tops.
Hoping it will be the same with 18350 tube. D4V2 i know will run flat top 18350, so then its just a question about the ft03 mini has springs like the ft03 and im well on my way to pinching a few pennies buying all these flashlights i really don’t need
Some lights don’t have the reverse polarity protrusions, nor a forward spring, but just a short ‘post,’ so flat tops will still work. My Sunwayman V11R and M11R have these and work with flat tops, even with no springs.
The tube really doesn’t come into play, so if you can run flat top 18650s in the standard configuration, you will be able to run flat top 18350s with a proper 18350 tube and even vice-versa, vis-a-vis flat/button tops.
From what I’ve seen (of course there might be exceptions), the only lights which need BTs are those with just the contact-board. No spring, no nipple, no nuttin’.
And even with the plain contact-board, a small solder-blob on the center pad lets you use FTs.