My first time using anything like this besides a standard 30cm ruler so it was a massive step up learning to use this to it's full potential. It really helped me to mark up my wood for perfect 90.deg cuts and also change to 45. with relative ease and If I was a roofer Im sure it;s many other uses would be utilised. It's a great usefull tool and looks very proffesional. I did damage it accidently whilst marking up Plywood from a pallet running the Square up and down the wood to discover a raised nail had scratched the paintwork but it still works fine. Very impressive high quality tool.