GRK TopStar 100mm (4") set of 24
GRK's shim screw - the Top Star™ - Allows window installation and adjustment without clips or shims. No more trying to air-seal around clips or fussing the window plumb and level. Substantially reduces labor for the installation of window and door frames (jambs).
Requires the use of GRK Crown bit
GRK Crown bit is the two-part drive system used with the GRK Top Star. The larger outer "crown" will drive both parts of the Top Star into the application. When you're ready to adjust the window or door frame, remove the "crown" and insert the remaing drive bit into the Top Star. Now only the "lag" portion of the Top Star will turn - in and out. This movement is like using a shim to either increase or decrease the gap between members.