Thule T-track Roof Box Adapter 697-1 697104. This adapter fits roof boxes directly into the T-track of the load carrier bar, offering an elegant alternative to tightening anything around the load carrier bar. It fits . This product is an authorized Thule UK stockist item. Brand: Thule, Model: 697104. Release Date: 5 October 2021. Compatible with 3.15 inch (80 mm) UB 0.79 x 1.06 (20 inch x 27 mm) load carrier bars.