Function: The machinist square ruler is ideal for precision layout and measurement work, highly preferable for professional engineers and wood workers. Squares are true right angles both inside and outside, can accurately measure the vertical deviation of internal and external angles. Proper Size: These machinist squares rules are include 63X40mm, 80X50mm, 100X63mm, 125X80mm. The proper size will ensure the accuracy of the measurement data, also allow you to hold the rule easily and firmly. Great Performance: The square steel ruler features thickened chassis, upright and stable, not easy to tilt, stand up on it's own nicely. So the measurement data is more accurate and easy to read. Just start from a known straight edge and measure, mark, then draw the line using this square. Nice Craftsmanship: Our machinist square ruler adopt quality hard carbon steel construction and bright surface, which is durable and stable. The smooth base surface make it safe for you. And the machinist square of each size is in a separate box, so it is easy to store and take. Easy to Identify: machinist steel square is engraved with dimensions and clear numbers, so you can quickly identify the data, which ensures that you can easily measure each right angle. The same beam and blade width and thickness makes it possible to use them in combination. Specifications: Size: 63X40mm, 80X50mm, 100X63mm, 125X80mm Material: carbon steel Color: silver Package includes: 4 x Machinist square Note: Due to the light and screen setting difference, the item's color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement.