My latest arrival 60s or 70s Waltham Vacuum Sapphire case (corundum) Swiss Made, not seen to often with an ETA movement, do not know whitch one, the day is non-quickset and the date is quickset.
Some say it is an ETA 2638 or 2738 and it could be a fast beat 36,000 bph

Great thread here, with some history.
https://forums.watchuseek.com/f11/an...m-1055835.html





Advert, very expensive back then.