The Empire Level e2994 rafter square is much easier to read and more durable than traditional silver squares because of its highly visible laser-etched graduations that will last for years without fading. The e2994 is constructed of 6063 anodized aluminum so it will not rust, corrode, bend or crack. It features a thicker edge than other products available in the market, which creates a safer saw guide. QR Code on back or square, use your smart phone to download the manual.