The Patek Philippe 570 came with one of four manual calibers (please excuse the “-” versus the use of “12’’’120”:
– 12-120 PS (PS: subsidiary seconds, “Petite seconde”)
– 12-120 SC (SC: center seconds)
– 12-400
– 27 SC
The most common movement found in the Patek Philippe steel 570 is the 12-120 PS.
Images: Phillips, Henry’s, Phillips, Phillips
This caliber was developed under Patek Philippe’s Technical Director, Jean Pfister, and replaced the prior 12-ligne LeCoultre previously used in the Reference 96.
The next most common is the indirect center seconds, the 12-120 SC, produced in combination with Victorin Piguet and included an additional mechanism connected to the existing 12-120.
Images: Phillips, Quinns
I have seen one example of a steel 570 with the 12-400 movement:
Image: Phillips
The 12-400 was introduced in 1949.
Lastly, I have found one reference to a steel 570 with 27 SC movement, but no image is shown. This movement succeeded the 120-120 SC.
If you know of any examples with image, please contact me.