I recently ordered a kit from Volcano, which said it was a model 501. Is there actually a 501 type, or is it really 510 and just a typo??? I'm a noob at this so was wondering if someone would be kind enough to clarify, and if so, what the difference is. Also, IMO a sticky with the different model numbers and a brief description of each would be extremely helpful for those of us just starting out. I'm really looking forward to trying this out, been smoking many years and am totally sick of it. This is a great forum, and I have definitely learned a lot from it, keep it up all....TY