I put my tablet with little force into the desired position, and then it stops.
The holder is indeed only plastic, but also stable enough.
After contact the Tablet wobbles considerably, but that is still acceptable for me.
The bracket gripper cover the Galaxy Tab-4 either the volume knob or the SD slot partially.
But I do not have to change the SD card when the device is in the holder.
But Beware:
If the tablet is provided with a protective sleeve, and thus is a little thicker,
may be too small, the rigid bracket gripper.
I could give only a little trick remedy, but it goes quite well.
Therefore 1 point deduction.