These are re-designed pieces to hold an 8 1/2" square piece of 1/4" glass in place on top of a Helios Heated Bed (from Panucatt) to get rid of the office clips that take space away from the build platform. It also gets rid of the springs under the bed that can cause some Y-Axis wiggle. This redesign adds longer sides to only leave a milimeter gap on each side to better hold heat under the bed.1) Print, install and check level. 2) Adjust and reprint needed corners or shim as required. You'll notice back right and front left have the same tab spacing so you can print 2 of the FronLeftCorner if you don't have wiring in the back-right area. I made a seperate BackRightCorner piece that has a built in notch for wiring (because my Y-endstop wires go through there).