Yup, what Thrasher said.
I don't wanna sound like a snob/elitist vaper but if you have to ask questions like: are there different voltages, amps. which battery should i use.
You are not ready for a Mech.
Mechs can be dangerous if the user is not knowledgeable enough about them.... So let me try to explain what they are.
Mechs are the simplest form of e-cigs that exists. They contain no electronics... they are nothing more than a metal tube on which you attach an atomizer that you activate by pressing switch that physically touches the battery. They are simple but requires the user to be knowledgable. They are not plug n play devices.
All of this means that means that they have no electronic circuits to protect you, itself and the battery. Unlike your regular e-cig that will shut itself down when the battery is "empty" or discharged, mechs won't, if you are not careful, they will keep going until it's to late. That means that you can over-discharge your battery... and that can be dangerous.
The voltage a mech runs on is the inherent voltage of the battery that is inside of it. The batteries that can be used with them are what is known as high drain IMR batteries DO NOT USE ANY OTHER KIND OF BATTERIES.
when fully charged, They start at 4.2 volts and will decrease in voltage (along with the vape) until it is time to charge them again (around 3.5 volts).
Most regular atomizer that you can buy, (protanks, evod, aspire, vivi novas, ce4, cartomizers etc...) will be performing terribly on mechs since they require more and steadier voltage.