Pull Rope Trolley with Four Steel Wheels. These rollers provide double steel wheels on steel bodies that are compatible with 16RT tracks. These trolleys are recommended for curtains 8 feet or taller. Designed to eliminate tugging or pulling on curtain when opening or closing. Roller provides a 3 inch wide steel plate with four 0.39 inch diameter holes to secure curtain panel to trolley. The curtain is secured to the two top holes when using 1 inch trolleys and is secured to bottom holes when using with 0.5 inch trolleys. Includes 10 foot polypropylene hollow braid rope with 0.375 diameter. Screw, nut, and 1.25 inch outside diameter washer included to fasten curtain to trolley.