Buy external dvd / cd drive?

I may need an external dvd drive for my laptop. What should I pay attention to when buying. So any technical data that is relevant?

Ne if it is only dvd can take any. Are not expensive.per usb shut and ready. You do not need msl nen drivers. Stop and go.

Nothing the things are technically mature.

If USB 2.0 then make sure that 2 ports are used. 1 x data with voltage and 1 x voltage extra.

The example: