D

120mr Thanks! You've noticed it! 😀 And this is waterworks identification plate. I found that D is for sliding bolt in pipes connection (I don't know all the signs). There are plates for gas fittings too. On the plate should be more informations (number of installation, diameter of the pipe and distance in meters) and I don't know why there isn't any. I found a pic from Warsaw how it looks like in the city tiny.pl/gfsp3

Satoshi T Oh Thanks! :) I understand that this plate represents the specifications about pipes! It seems like the specs under the pics we are seeing at Tookapic :) . Camera-type, aperture, focal-length ...

120mr Numbers, numbers everywhere!