Was following the Quadlock charging station thread and several comments were made about some phones, typically iPhone, not surviving a pummelling on the stem mount. Looks like they are aware of the issue with some phones not liking a shake! https://www.quadlockcase.co.uk/pages/quad-lock-vibration-dampener
To be fair it’s not just them, read of people having same problem with other popular mounts too. Would be nice to think they might offer these at a discount to those who have already purchased their mounts?
