Currently, almost all led fluorescent lamp with built-in power supplies are on the market. The so-called built-in refers to the power supply can be placed inside the tube. The biggest advantage of this built-in is that you can make a direct replacement for existing fluorescent tubes, without having to make any changes to the original circuit. Therefore, the shape of the built-in power strip are usually done growing, so go into the semi-circular lamps. There are two built-in power supply, a non-isolated, one is isolated.
Non-Isolated refers led the load side and 220V inputs have a direct connection, there is the danger of electric shock load and therefore touch. Only isolation between 220V and aluminum thin insulating layer of aluminum plate, usually not easy to pass CE and UL certification.
Isolated refers to the input and output of isolation transformer isolation transformer may be a high frequency power of the frequency may be. However, both the input and output isolation up. Avoid the risk of electric shock. Also easy by CE or UL certification.