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 4 foot polypropylene hollow braid rope with 0.375 diameter. Screw, nut, and 1.25 inch outside diameter washer included to fasten curtain to trolley.