Congratulations Brook, it's a nice one. These are both rare and have a special place in the Heuer firmament - Heuer had the patent for reading a pulse from a scale on a watch, having invented it in the first place. Some of the pre-Carreras used it too, but we don't see it often later on. It's in the combi-scale used on Monzas etc but I can't think of many watches that used it discretely after these 2447s.