Hehr 1600 and 4600 series jalousie windows require small 3/8" diameter rubber pads to be squeezed between the glass and aluminum window frame one on each end of each piece of glass in the window (2 per pane). The button-shaped pads help hold the glass securely in the window.
Originally, those discs were made of gray vinyl. Over the years, the vinyl cracks and hardens, allowing the glass to come loose. Proper maintenance of jalousie windows includes checking these discs for age damage and replacing them as necessary.
Package of 25 buttons. They are approximately 3/8" diameter and 3/16" thick. They are made of gray silicone rubber which does not crack with age the way that vinyl does.
Old Hehr PN 009-125. Slightly thicker than Hehr 009-265 which was used on the Hehr 2400 series windows.