Tandem Roller Assembly with 1-½ inch diameter  Center grooved concave wheel for heavy Sliding Patio Doors 
This Roller Assembly has Steel Ball Bearings 
This design is used by manufacturers such as Arcadia Armour Vue Atlas  Pella and others

Housing Tab Style: Plain Back 
Housing Width: 7/8-inch 
Housing Height: 1-13/16 inch 
Roller Diameter: 1-1/2-inch 
Roller Edge Type: Concave 
Roller Material: Steel 
Roller Width: 5/16-inch 
Contents: 1 roller assembly , sold Each

Related Door Rollers: 
13045 - 1-1/2 inch wheel 
13047 - 1-13/16 inch  wheel