Window snap bead..?

[Ryan R.]

I've got a rehab with either aluminum or metal windows that look to be about 20 years old. The snap bead that surrounds and helps seal the perimeter of the window is brittle, faded and unsightly. Home Depot has snap bead but it is smaller than what I need.

Any tips on where to find this bead? Any solutions for using the bead at home depot with some modification? How are these beads measured and classified? I can't find any branding on the windows.

I'm going to try some local glass and window shops but thought I would check here first.