How do I leave a review? November 22, 2018 13:09 Updated You can leave a review directly on our product page here. All reviews are approved if you're a verified buyer. Thank you in advance for the feedback! Related articles The touch gestures are inconsistent I have an anxiety disorder. Could doppel help me? Do I need a smartphone to use doppel? There aren’t any screens or buttons, how do I control doppel? Is doppel waterproof? Comments 0 comments Please sign in to leave a comment.