I hear a zipper running up, and a moment later the complete works of Shakespeare smash into the wall beside me.

In the kitchen he heard a zipper-rasp as she opened her parka.

I heard a zipper unzip, her heavy sigh.

Annja heard a zipper being drawn down and a second later, Vic handed her a small cardboard box.

I heard a zipper, and she took my hand and put it on her crotch, then pulled the cotton of her underwear aside.