Lock button - Ruler with locking knob designed to lock the angle at any convenient position. A variety of uses -Ruler and protractor 2 in 1 for easy measurement.Digital display - The LCD is clearly displayed for quick and easy reading of measurement results. Fast and accurate - Digital computing systems make angle and length measurements faster and more accurate. Practical and durable - Protractor ruler is made of stainless steel and has a long service life. Material: Stainless steel Measurement Range: 0-360, 0-200mm Resolution: 0.05 Accuracy: 0.3 IP Rating: IP54 Operating Temperature: 5~45 Operating Humidity: 85%RH Battery: 3V CR2032 Battery Weight: 228g / 8oz (approx.) Package list:1 * Protractor Ruler.