Summary

This mount clamps to the headstem of your bike and secures the DJI spark controller as you ride. Use this with Active track so you can control the spark to bring it closer or dodge trees. You will need a small velcro strap. I used this one 200mmx15mm https://www.banggood.com/RJX-HOBBY-Magic-Tape-Tie-Down-Strap-for-RC-Battery-p-1134012.html?rmmds=search&cur_warehouse=USA
You should also attach some 2mm thick foam adhesive sheet to the headstep interface and a small square to the inside bottom of the mount to stop the controller sliding left to right.
Recommend to mount your phone in a separate location on the handlebars using elastic bands or something like a Quad Lock.
I use PLA+ since it has less warping than ABS and seems very strong.