The plastic of which the holders are made is very durable and well made. The two holes for attaching the bracket to the wall are slightly wider than milled circular, so you still have room for maneuver when tightening, if the holes were not put 100% horizontally. The swivel head provides enough freedom of movement to bring the boxes to the desired, aligned to the space center position. Using a screwdriver from above stated, the joint head can be screwed tight enough.
The vertical position of the joint head is held by grooves are on the hemispherical inside on the surface, which are to get caught with the grooves on the likewise hemispherical head of the bracket. I use quite small boxes, but have all the screws more tightly. With me everything keeps properly, but the speakers are well below the maximum weight.
Desirable I would have found it when the joint of the bottom of the holder could be screwed. I have in my living room on the side where the TV is, from about 1 m altitude a sloping ceiling, and attach the boxes there in the corners, was a terrible job, because you just could not start from above the screwdriver in this case as it was intended for the holder, and thus could screw it difficult to determine the holder.
The screws for the boxes were supplied, but fit in my case, boxing is not because the speaker thread was made for English 1/4 inch screws. But even this can be used with the brackets. Although the pre-milled hole in the joint piece is minimal too small, but the plastic is to clean the bolts.
