I thought I would never find of these for sale! Very excited.

I present to you an early Polerouter Jet. The dial resembles in many ways the dial of the Longines reference 8888. Very beautiful and classic:




But what's really makes this one special is the glass back:




As far as I understand, these glass-back models are factory original and were never intended for sale. It is what is called a "salesman's model". Just as some pocket watch manufacturers did in the early 20th century, UG decided to send these models out to their retailers to wow potential customers (in UG's case, to show off shiny new microrotor technology).

I can think of few automatic movements that deserves a glass back more than this beautifully finished microrotor from UG. Bravo!



One question I have, though... is whether this is safe to wear regularly. I assume is was never intended to be worn extensively.

 

Verrry Nice!

 

Care to unscrew the caseback for some detailed photos of the back crystal?

Nice pickup. And nice slinky

 

I am inclined to agree with you, Lous.

It would be wrong to wear it extensively. I will search out a metal back, should I decide to wear it.

Sure woodwkr2,

Here are some photos. I believe it's a plastic back. Hugging the threads is an old washer. The metal rim is veeeeery slim.

 

Is the acrylic crystal plain or does it have an inner compression ring?

Depending on the dimensions of the caseback, a standard replacement crystal may be fitted. In which case, I'd replace the original with a generic (safely stashing away the original) and then wear it worry free.

I see the soundness of the advice to replace with a metal caseback out of an abundance of caution, but if you have a good fit with the crystal, what's the danger?

Put in it a vacuum chamber dry leak tester (like my Elma device) with some new gaskets and test it. If it passes, it's surely good enough to keep wrist sweat and grime out of the movement as well as the crystals perform at their usual task of protecting the dial.

 

I examined it closely and it seems to be just plain crystal. I will look into the options.