I am using a TW Tornado and I think the carts hold about 19 drops on the whistle tip. Does anyone know how many drops a 510 cartomizer will hold? And will they work on any 510 atomizer because on dietsmokes.com he is selling them as a 5 pack but then 1 with an atomizer and a cartomizer. It didnt make sense to me. Also wheres the cheapest place to get them? I only need the cartomizer not the atomizer.