Tandem (2-Wheel ) 1-1/4 inch Nylon ball bearing roller and Steel housing 

Dimensions: thickness 11/16 inch; length, 4-5/8 inch; height 1-3/16 inch
Screws holes spaced at 5-3/4 inches. 
Sold each, priced each

Diameter: 1-1/4-inch
Housing Tab Style: Unique Housing
Housing Width: 11/16-inch
Material: Nylon
Roller Diameter: 1-1/4-inch
Roller Edge Type: Concave
Roller Material: Nylon
Roller Width: 5/16-inch
Type: Concave
Width: 11/16-inch

Related Items: 
13090 - 1-1/4 Nylon 
13243 - 1-1/2 inch Nylon Wheel 
13093 - Steel wheel 
13232 - Stainless Steel Wheel 

How to Adjust Sliding Door Rollers