Beyond the font and numeral layout there seems very little in common. I don't quite understand how the non alarm variants (virtually all but the I and R's) retained the word "vox" in the name as it means "voice", a synonym for the alarm complication and used throughout their alarm models for decades. I'm very intrigued by the pivot chrono feature and it is absolutely unique but have been unable to pull the trigger due to the thickness of that complication. As a consequence I've had a couple of 1's but still drawn by the chrono and still yet my make one a stable mate.