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Greetings, I'm Tim of Govberg, and welcome to the world of IWC. Today, I'll be your guide to the proper usage, care, and maintenance of your IWC Portugieser Chronograph, reference 371491. This is an automatic winding timepiece by means of caseback winding rotor, and it can energize itself when worn on the wrist. However, should you wish to manually wind the watch, simply turn the crown in its first position flush to the case, in a clockwise direction 20 to 30 turns, or until you see the seconds hand at 6:00 advancing. Now you can set the watch.

In order to fully wind the watch, should you wish to maximally energize it up to it's 44hour maximum rated power reserve, simply continue turning the crown, and listen for a subtle click or tick within the case. That's the bridlestyle mainspring slipping by design. It's designed to avoid accidental over winding by automatic or manual means. I repeat you cannot accidentally overwind this timepiece. So, wind until you hear the slip. Now, your watch is fully energized.

The stop seconds function allows you to precisely set the time of day to the second on your watch. The best way to do this is to wait for the seconds hand at 6:00, to reach the index at 60. Pull up an online atomic clock, such as the one at the US Naval Observatory, so you have the precise time to the second. Pull the crown out to a stop when the hand reaches 60. And now you can advance to set the time to the hour and next nearest minute, relative to your reference time, the atomic clock. Wait for the clock to catch up to the time you set on your watch, so that the hour, minutes, and seconds match precisely. At that very instant, push the crown in. Resume the beat of the balance. Now you've synchronized to your reference time.

The chronograph is a traditionalfashioned chronograph, which is to say it does not have flyback functionality. It's operated in a start/stop reset fashion. With the pusher at 2:00, push down and start the chronograph. Push down once more to stop. You can resume the beat of the chronograph, but the chronograph must always be stopped before you reset.

There are three principle areas of hazard when handling your watch that you should keep in mind. Water, magnetism, and shock. Keep in mind that leather, a natural porus material, is never waterresistant, and should be kept remote from moisture at all times. The timepiece itself is waterresistant to three ATM, or 30 meters static test depth. What this means in practical terms is that the watch is protected against inadvertent splashing while washing hands, or should you be caught out in the rain, the watch has sufficient hermiticity to resist that level of moisture. The watch should not be used for swimming or aquatic sports.

You can help avoid accidental drowning by keeping the chronograph and the crown disused. Do not wind, do not set, do not start, stop, or reset the chronograph when there's water on the case, as this can bypass the case seals, and introduce water to the interior of the watch. Water resistance is not a static feature of your timepiece. Unlike mechanical specification, water resistance will ebb with time, as lubricants and seals age and degrade. Therefore, IWC recommends having the watch watertested once annuallyat an authorized service center, to ensure that factoryrated water resistance is retained.

Though it will not cause permanent damage, magnetism can severely affect the precision of your timepiece. The hairspring at the center of your watch is balanced. Effectively its heart can become magnetized in the presence of highpowered wires, speakers, subwoofers, MRI equipment, as well as the closures of purses, wallets and refrigerator doors. Keep the watch remote from all of these, and if you suspect due to erratic timing, fast or slow, that your watch has become magnetized, take it to an IWCauthorized service center, where specialized equipment is available to quickly and easily demagnetize the watch.

Finally, with respect to service, IWC recommends every three to five years, a comprehensive overhaul. This will include restoration of factory case finish from all aspects, restoration of watertight integrity, replacement of a worn strap, if necessary, as well as cleaning, oiling, and adjustment of the mechanism. Performed exclusively at an IWCauthorized service center, or the factory itself, in Schaffhausen, as these agencies solely are able to protect the investment and instrument value of your watch with trained personnel, specialized tools, and original IWC factory replacement parts. Moreover, only these agencies are authorized to back all labor and parts invested with an IWCfactory service warranty.

Finally, call text, or email our experts at govbergwatches.com. We'll be happy to walk you through every phase of the ownership, use and care of this or any IWC fine timepiece.