So yes, the epoxy-type paint above is not fully applied, this support is basic. But in fact, this is what I wanted, we see not behind my computer screen (22 inches) that is secure, and above all it is not expensive at all !!! Simple to implement, with a small integrated level.
You just keep in mind that this support is thin, and the configuration of connection behind your TV or screen, cables can interfere. It took I bought a 220V power cord with an angled connector, and now it's perfect.