I don't know if because of a factory defect or not, but my adapter has a super powerful spring. It could have been an advantage.. if I only had readed the veeery small warning on the box in time (without any instructions on how it works on it):
"Never try to deploy (twist) the X-15 adapter before mounting it to your friame" ( which I did immediately, hurting my arm. :/ )
In my opinion the warning text should be HUGE: I felt the spring vibration up to my shoulder. 2 stars, not just one, because, as a customer, I should have paid more attention.