36 mm (1.417inch), 38 mm (1.496inch), 40 mm (1.575inch), 42 mm (1.654inch), 45 mm (1.772inch), 47 mm (1.85inch), 50 mm (1.969inch)
The two spikes on top of the ring are adjustable. This spikes are covered. Through this any manipulation is not possible. The corresponding key is enclosed. The 4 spikes below at the ring have a length of 5mm (0.197inch) and are not adjustable.