Just received it. Use on duke 250/390. For the money, it seems like a good value for money, very convenient and functional. I don't know about its durability in long-term use.
It is NOT made of aluminum as described. 100% plastic.
The clamp tightens well on the handlebar, with the option of one of the two adjustment rings of different thicknesses it has (and it can be installed alone, without the main "body", if it is not for permanent use).
As soon as the phone is placed in its position and pressed slightly in the center, the clamps close automatically (with internal springs, which may be the weak point in long-term use and weather conditions) around the phone. It opens and removes the phone from the base with one hand, by pressing the two protruding tabs on the side of the base.