Review on 🚗 SHOWSEN Rear Passenger Power Window Regulator w/ Motor for Dodge Dakota Quad/Crew Cab (00-04) Durango (98-03) - High-Quality Replacement Part by Adam French

These are two rails that slide up and down the rail when the window is lowered/raised. The rail at the top slipped off the rail when the window was all the way up, causing it to bind when trying to lower the window. Either the quality control isn't doing its job or it's just a poorly designed part. UPDATE: I later found that I was missing the mounting clips on the window itself, which would explain why the rail went off track. I'm still not sure where it went, but I didn't want to blame the manufacturer.