They are using different movements, although both are thermo compensated.
The 27-jewel
ETA 251.233/1 in the black bezel 2VEV boasts a tolerance of just -15/+15 seconds per year, with 12 hour chrono whereas . . . .
.
.
. . .the
ETA’s 251.274 in the steel bezel 1 VEV is a 22-jewel, 30mm movement boasting a tolerance of just -10/+10 seconds per year, with (by the look of it) a 30 minutes chrono and a 'Time-Zone Mechanism' (Independent hour hand).
Also the ETA 251.274 CF calibre is a 13¼’’’ multi-function chronograph movement displaying hours, minutes, seconds, date and incorporating PowerDrive and PreciDrive technologies.
The ETA 251.233/1 does not come up on a search on ETA's website. Retired movement perhaps?
The earlier C65 AM GT, gets an
ETA 251.264 COSC rated (as we know).
Although the movements in the 1VEV and 2VEV are not, it would appear, COSC certified they are nevertheless PowerDrive and PreciDrive, so ultra accurate (even though not tested as such).
Yes; I will agree there are some muddy waters on the earlier qualification of the C65 AM GT being 'the last quartz watch'.
However, I will ask if there are enough similarities between the GT, 1VEV & 2VEV for them all to be considered part of the C65 AM . . . family; being the last CW Quartz watches.
Guy
In small proportions, we just beautie see:
And in short measures, life may perfect bee. - Ben Jonson (1572 – 1637)
Inscription on the
Longitude Dial
Hatfield House, Hatfield, Hertfordshire AL9 5NB, England