Do these rails look familiar to anyone?

[Garrick David]

I found these rails (see attached photo) at a surplus yard. I think they would work for a project I am working on.

I could make bearings for them, but if I could find out where they come from I would prefer to buy something that was designed specifically for them.

Thank you,

Garrick

[Rich Lester]

Garrick,

I work part time for an aluminum window manufacturer and these look like what we call a sill starter for aluminum window instalations. Basically a sill starter is set down on the opening condition to lift the window off a set distance then the window is set in place on it.
Just saying that's what they look like to me.