0-60 Degree Adjustable Aluminum Alloy Guide Rail Clamps for Woodworking - Track Square Edge Positioning Clamps for Circular Saw & Power Tools - Perfect for DIY Projects, Cabinet Making, and Precision Cutting

First off, this is extremely well made and once setup (see below) very accurate and repeatable. It is a direct clone of the Woodpecker model, but less than half the price and I see no real difference. The tab at the end to keep it from tipping the track when using it is also a nice touch.I almost sent this back when I first got it, due to it being a full degree off 90 when it arrived. The small instruction sheet does not mention any method to calibrate, but if you loosen the Allen screws holding the marking gauge on, you can easily calibrate the gauge and make the detent accurate.The only minor drawbacks to it, are the weight (it's pretty heavy), and that it is one sided so you can't slide it to the other side of your work, it has to be used on the edge closest to you. I gave it 4 stars due to the mis-calibration issue, but 5 stars once dialed in.