GRK's VWS Vinyl Window Screws are designed to quickly adjust windows to plumb alignments without tedious measuring. The patented Vinyl Window Screw makes setting vinyl windows a breeze. By catching the window frame between the screw head and the screw's secondary shoulder, the window position can be quickly and easily adjusted. Our product is perfectly suited to meet the needs of both professional and do-it-yourself installers. Simply pre-drill the first layer, insert screw, lock collar and adjust... it's just that easy.