Printed at 40% infill. No supports needed. I used these magnets from amazon and super glued them in place. The holes should fit up to 20mm magnets just a bit more snugly. You'll need to fill all 6 slots in order for this to hold a 16 oz beer or 12 oz bottle. If you need a coaster for bigger glasses I've got a similar design here. This took just over 7 hours for me to print.
The author hasn't provided the model origin yet.