Introducing the plastic composite peel-away shims by Glazelock! Industry standard alignment and leveling of doors, windows, stairs, cabinets, counters, sheetrock, drywall, furniture, machinery, plumbing for DIY'rs and professionals alike! Made of High Impact Polystyrene plastic, these shims can also be used as tile spacers and won't rot, shrink or swell. The U-shaped design allows the shim to fit around bolts and anchors, making install more streamlined.