# What are the two orange tabs stuck on opposite edges of each window of the ISS cupola?

The YouTube video ONE OF THE MOST DETAILED ISS TOUR!!! is cited in several Q&A here, and shows a tour and explanation of the ISS by astronaut Steven Swanson.

Today I noticed between 28:30 and 31:20 that each of the seven windows in the ISS cupola shows a pair of orange stick-on tabs on opposite edges of the glass. Sunlight can be seen through them, showing what looks like four circuit board traces and three "pads".

What is the function of these devices, what do they connect to, and have they always been there?

I'm guessing they are not for security or burglar detection.

above x2: Screenshots from here, first is zoomed/sharpened.

• Those traces make me think of thermistors. Maybe the temperature of the glass is measured here? – Dragongeek Nov 13 '18 at 12:04
• @Dragongeek: I agree, it may be an RTD in four wire configuration for temperature measurement. – Uwe Nov 13 '18 at 12:10
• "Thanks", @uhoh! I've never noticed those tabs before and now I see them in every picture! :) Like the "cue dots" in old films, once my projectionist friend showed them to me, I could never un-see them. – Organic Marble Nov 13 '18 at 15:10
• @OrganicMarble exactly, me too, same thing (re windows, not cue dots, but now that you mention it...) Perhaps it's a glitch in the matrix type thing. – uhoh Nov 13 '18 at 15:18
• Probably just hinges to open the windows when it gets hot on the ISS... ;-) – agtoever Nov 14 '18 at 8:14