Horizontal Sliding Window Roller

No manufacturer nor markings available. I am a condominium owner and like to be a handy person.

This roller seems to be the STB type. I don't know what that stands for.
Do you?

The dimensions of this roller are described in the table on both pages.

The diagram is one which I found resembles the roller except there is an axle on the roller and the center turns so the wheel can roll. Each slider uses two and there are four needed for each unit.

The dimensions on the diagram are for another roller, but mine is different. My measurements were made with a micrometer used for steel sheet.

These windows were installed in a 153 unit condominium and ride in a channel.

Sure, here you go. wheel diameter: 9/16", axle diameter: 1/4", wheel thickness: 1/4", axle length: 1/2"