The RN4081 is often referred to by many alternative names. It is sold by many huge suppliers. Some common names are the NJoy NPro, Smoking Everywhere Gold as well as other names. It is legendary for looking like a real ciggie.
they also are famous for having robust atomizers and good vapor production. The cartridges are very small as are most cartridges of electronic cigarettes that look like cigarettes. That suggests they hold little liquid and you have to constantly refill them or buy new cartridges.
To refill these cartridges first you have to disconnect the cartridge from the atomizer. Then you simply add drops to the tiny inner cartridge till it's full and with the atomizer push it into the cartridge.
The atomizer is easy to maintain. After that wash it under hot water and blow all the excess water out the same way. A large amount of times after cleaning it works better than ever before.
The battery lasts 2 hours under heavy use so it is often commended that you have a spare battery.
As with all electronic cigarettes it's always suggested to have spare parts since parts can fail at any time. You do not need to get stuck having to buy cigarettes when being prepared and having spares isn't that expensive.
the number one place to get the RN4081 is at RN4081 E-Cigarette. They have the most competitive prices and fast shipping.