This is a mount for the ProGrade card readers, specifically the dual sd card and cf express type a model. The mounting system uses double sided tape (I used the 3m vhb thin tape) so it sits flush with the top of the mounting area. It is a two part design with a snap on back cover with a hole for the usb c cable and has venting holes in case of hot temps. It is designed with a gap between the top of the card reader and the plastic housing to prevent heat damage.