This is a solid piece of CNC machined aluminium, high quality, highly durable and extremely accurate. The GRS-16 guide rail square fits onto either Festool or Makita guide rails. Its beauty lies in its simplicity; connection to your track takes a mere 5 seconds. There are no loose fixings or loose parts to get lost. The GRS-16 is self-aligning, simply slide it into the T-slot on the underside of you track and then close the latch. The latch locks firmly, ensuring the 400mm long reference edge is at precisely 90° to your track. There is a small notch in the front of the reference edge to allow you to use a guide rail clamp for extra security should you so wish. Once fitted this guide rail square allows you to set your guide rail at a perfect 90°, in an instant, every time. The speed, accuracy and the ease of use this guide rail square is well worth the investment.-bg