Differences between Viessmann heating rod & No Name?

Hello,

I wanted to buy a Viessmann electric heating element with 12kw, then I saw that there are basically identical-looking heating elements from other providers that don’t say Viessmann and cost less than half.

Does anyone have experience with them? After all, isn’t it more or less just a plastic housing with a resistor and a shielded heating coil/wire through which electricity is passed?

I am inclined to buy the cheaper one.

Thanks for your opinions/experiences.

Best regards