"The D shaped pallets of Harrison's escapement are both made of diamond, approx 2mm long with the curved side radius of 0.6 mm; a considerable feat of manufacture at the time.For technical reasons the balance was made much larger than in a conventional watch of the period, 2.2. inches (55.9 mm) in diameter weighing 28 5/8 Troy grains (1.85 g) and the vibrations controlled by a flat spiral steel spring of 3 turns with a long straight tail.