Thank you for your inquiry. Yes, you are correct in your assessment. The 4.33 inches specification refers to the maximum adjustable beam flange width that the trolley can accommodate. The interior plate-to-plate distance is designed to be adjustable within the range of 2.68" to 4.33" to fit standard I-beams. Since your beam (USS8X8.81) has a flange width of 4.262", this trolley should fit, as it falls within the product's maximum capacity of 4.33".
By vevor