GRK Fasteners TOP STAR 20161 Shim Screw 3/8 in Thread 3-1/8 in L Flat Head Star Drive Steel Zinc 100 BX

GRK's adjustable Top Starâ„¢ shim screw, is in fact a screw within a screw that allows you to install wooden doors or windows without the use of shims. The quick and easy system reduces labor and allows for hassle free adjustment to ensure plumb installation.