I hope you had a successful China show .
I finally met with all related , and confirmed as follows.
All 3 units sent back were brand new products we received from you.
We found problems with 3 units. We sent you the video first to ask your
suggestion. You suggested us to send them back for the further inspection there.
This is the history of this issue.
1st unit: could run maximum motor speed only 48 rpm.
2nd unit: indicated error code on the display
3rd unit : hand-piece generated unusual heat
What would be the next step you suggest please