|Winding:||Automatic, Bi-Directional Automatic Winding|
|Diameter:||29.00 mm (13 ligne)|
|Complications:||Date, Day, Hacking Seconds, Hand Winding, Outer Day Wheel, Quick Date Correction, Quick Day Correction|
|Hands:||Central Hour Hand, Central Minute Hand, Central Seconds Hand, Date Window at 3:00, Day Window at 12:00|
|Production: 2017 – Current|
STP4-13 is an automatic watch movement with day and date wheels from Swiss Technology Production. It is based on Cal. STP1-11, itself a clone of the popular ETA 2824-2. STP uses a longer, thinner mainspring, boosting power reserve to 44 hours. It also includes an extra jewel on the barrel arbor.
The Day-Date STP4-13 uses an outer day wheel like the ETA 2834-2, increasing the diameter of the movement to 29.00 mm. Cal. STP4-13 was first introduced in 2017 and remains in production today.
STP may have used an ebauche from Sea-Gull in China to build the STP1-11 family. Photos on the company web site previously included the label, “ST2100”, which is the identifier found on the Sea-Gull ST2130 movement. The same has been said of the Valanvron VAL-24. Due to their Swiss content and finishing, STP can legally classify these movements as “Swiss Made”, and the company may now construct most or all of the movement in-house.
|Swan Neck Regulator||STP3-13|