I'm curious why you are thinking about the SMPL mechanical? Have you done much research on this class of mechanical mods? I know you are relatively new to mech mods in general is why I ask.
The SMPL is a hybrid-top, pinless direct to battery mod, not generally recommended for new mech users because of their inherent increase of danger. You can't put just any type of atomizer (esp not a clearomizer) on a direct battery mod. The 510 connector MUST have an extended center pin.