This model was designed to secure the glass top and heat spreader to the build platform without binder clips. The corner can slide in and out to secure or release the glass top. The design is used in the Artifex 3D Printer (http://www.3dmakerworld.com/artifex), and can be used in many other 3D printers as well. Installation instruction is provided in the Artifex Build Instruction: http://www.3dmakerworld.com/support/documents. The model was designed in Alibre (now Geomagic), and the source files can be found here: https://github.com/3dmakerworld/artifex.