Discontinued, no longer available. 

4-Wheel Hanger for Pocket Door

Roller Diameter: 5/8 Inch
Roller Height: 1/2 Inch
Roller Length: 1-3/8 Inch
Base Width: 5/8 Inch
Base Length: 1-7/8 Inch
Rollers: 4
Material: Plastic, Aluminum

Contents: 1 Roller, 1 Base, 2 Screws

Priced and Sold Each.