Nanos Single tube | mmvapors.com
For an authentic I would recommend the Nanos by MMVapors. It is one of the lowest price, highest quality mods available. The locking action of the switch is very unique in that it uses six tiny magnets for the locking function as well as the spring function. You only have to "flick" the button with your little finger to lock or unlock.. Only rotate the button 7mm. The contacts are not copper, but Rhodium over silver coated brass which hardly ever needs cleaning and always gives great conductivity.
MMVapors has very good customer service, quick three day shipping from Europe, always in stock and every single spare part is available if ever needed.
They are coming out with their own Dripper at the end of this month. I will be getting the dripper, even though I don't have much detail on it at the present as they have never released a bad product.
I have one of the Nanos and two of the side switch Poldiacs they build and have been very pleased with them and use them daily.