47" lengths.

Stainless steel construction with felt and pile lining.

Bottom track has shoulders, and the exterior dimensions are: 1/2" wide and 5/16" deep below the shoulders. The inside of the track allows room for 1/4" thick glass or plexiglass. 

Top track has no shoulders. Exterior dimensions are: 9/16" wide and 9/16" deep. The inside of the track allows room for 1/4" thick glass or plexiglass. 

1/4" is ideal thickness for glass or plexiglass. 3/16" can work, but it will be a little loose in the track.