The Schatz 1000 day clock was not a bold step forward because it just increased the time between winds.
They were able to increase the time from 400 days to 1000 by taking the 400 day movement and putting in a mainspring that held 2.5 times the energy.
You can tell when one was made by looking at the month and year stamp on the back of the movement.
|Very Nice Rare Vintage SCHATZ 54 1000 Day Anniversary Clock FULLY FUNCTIONAL|
Time Remaining: 14h 26m
|UNIT 10B SCHATZ 1000 DAY ANNIVERSARY CLOCK 54 SUSPENSION SPRING WIRE UNIT 400|
Time Remaining: 16h 14m
Buy It Now for only: $42.99
|Schatz Mainspring Anniversary 1000 day clock 21 x 50|
Time Remaining: 20h 49m
Buy It Now for only: $26.49
|SCHATZ 1000 DAY GERMAN ANNIVERSARY CLOCK VINTAGE MAKES A BEAUTIFUL GIFT|
Time Remaining: 1d 4h 48m
Buy It Now for only: $454.95
|Schatz 1000 Day Dome Anniversary Clock Runs Excellent with Key|
$76.00 (4 Bids)
Time Remaining: 1d 12h 33m
|SCHATZ 1000 Day Anniversary Clock 54 German|
$46.00 (13 Bids)
Time Remaining: 3d 5h 38m