it's all about sony vtc4's I understand there is a 5 out there but I thought I read it's for 26650 mods. You are going to want to look for ICR (LiCo02) and IMR(LiMn) some other brands are MNKE, Efest. You will want to be careful with the batteries so do some research online google or whatever.
this is rife with misinformation and I have to set it straight.
Sony US18650VTC5 are an upgrade to the VTC4 and are the same size and shape.
ICR batteries are DANGEROUS and have no business anywhere near a vaper. they belong in flashlights, which are far less demanding.
Efest are junk. They overrate their batteries, saying they can do more than they really can. and they use cells that don't pass first tier quality control.
Battery safety is hardly a "or whatever" topic