Ball and socket style mount that goes behind the trim on 2015 to 2019 Silverado, Tahoe, Suburban, etc.  May also fit other trim pieces on other vehicles.  Ball is 17mm.  I use it for a phone mount as well as to mound my Edge CTS in my truck.  Works great.  I printed in PETG and ASA.  PLA will not hold up to the heat in the vehicle.  Enjoy.  Thanks