On mine, there was a blue plastic strip the I peeled to expose the sticky. Yes, it is a mother if their is no sticky. On the first window I did, I did not know the sticky was covered by the plastic, and was having one hell of time trying to get everything in the right position, and the second pane on top, and getting the spacer to stay in position. I was going to use some contact cement to get it to stay in position, when it melted the plastic covering the sticky on the spacer. Then, I saw the light, and from then on, it was a snap.