Quadrant Shower Enclosures. Quadrant Trays. Quadrant Stone Shower Tray +Riser Kit (Optional). Square/Rectangle Stone Shower Tray +Riser Kit (Optional). You have to leave space for the waste and pipe to run in the floor,so you can not install the tray on a concrete floor.If you want to install the tray on a hard floor,pls buy the riser kit from us.