CRL Aluminum H-Bar is used most often for showcase sliding doors. Designed for use with 3/16", 7/32", and 1/4" (5, 5.5, and 6 mm) materials. 3/16" and 7/32" (5 and 5.5 mm) materials require the use of DV765 Vinyl for proper fit. You can use either the D650 Nylon or D649 Steel Wheel Units with this H-Bar. Both the GC728 and DV765 vinyls are designed to accommodate 1/4" (6 mm) glass providing a tight fit in this H-bar. GC728 vinyl has an extruded lip which, when seated, leaves a visible neat "bead". The DV765 sits below the face of the H-bar leaving an unobstructed view of the glass.