The charger design allows for a much smoother charge and mugs will charge quicker than the standard chargers. Also there is less likelihood of a mug not charging when placed slightly off centre as the sides are higher and are better at guiding the mug onto the pins. They also have a smaller footprint and take up less desk or surface space. 
 
Charges both a single mug and dual mugs with a single plug socket for locations such as the kitchen where power sockets and space may be limited. 
Details: The coasters are made of 3d printed parts and other components sourced from manufacturers. The chargers are compatible with all Ember Travel Mugs, Tumbler's and Mugs.
Low cost alternative to an Ember Charger.
All Mugs, Travel Mugs,  Tumblers 1st and 2nd Gen are supported along with compatible devices such as the Nebula mugs.
The coasters are very stable and the mugs naturally sit in them and charge immediately on contact.
The charger base are also compatible with existing Ember chargers, If you wish to use a USB-C charger then you will need a PD2 or PD3 charger with an output of at least 45w and support for 20v output.