... alloy frame 3.high accuracy,high quality Multi-Function angel finder Aluminum alloy silvery white oxidation surface Five glass level bubbles in ... black plasc Four bubbles indicate 90°, 180°, 45°, and 0°-7° Accurate to 0.029 ... °= 0.5 mm/m for 90°, 180°, and 45°. Accurate to 0.86°= 1.5 mm/m for 0°-7 ... tube’s tilt at 0°-7° Hot Multi-Function level (New type),spirit level