Cal. 3126 is an automatic chronograph movement from Audemars Piguet often used with modules. It measures 29.92 mm (13.25 ligne) in diameter and operates at 21,600 A/h. It appears to be based on the Valjoux 7750.
- Audemars Piguet Royal Oak Offshore 44, Ref. 26400, 26401, 26405, 26408, 26411, 26412, 26415, 26416 (Cal. 3126/3840)
- Audemars Piguet Royal Oak Offshore 42, Ref. 26237, 26470, 26471, 26473 (Cal. 3126/3840)