Pros: Barn door rollers there are little bumpers on each side for the trolley to come up against a stop. The body has a recess for a bolt head to keep it low to prevent hitting the mounting bolts of your strut. Cool design feature! It comes with a long bolt which you can use to adjust the height of whatever you hang from it Operate Steadily:Beam trolleys standard deep groove ball bearing installation,is very smooth no noise to it when used. Bearing welding positioning,to ensure the stability of the work Easy Installation: You will receive 2 sets of sliding door rollers, each trolley assembly comes with one M10 bolt and two nuts for quick and easy installation. Simply mount them to the strut channel and they are ready to use, saving you time and labor Unique Design: Unistrut rollers features a special groove design with hidden fastening bolts, ensuring smooth movement along the channel.The side protrusions protect the bearing from impact, increasing its lifespan Wide Compatibility: Barn door trolley fit 1-5/8 inches wide and all 1-5/8 inches or taller strut channels,M10 Bolt in the middle, 92 mm (3.6inch) in length,2 nuts are include that is better for upside down used Material:4 Wheel trolley assembly roller manufactured from stainless steel,the trolley assembly offers high strength, corrosion resistance, and durability, making it suitable for various applications such as barn door or garage door replacement Heavy-Duty Performance: Strut Channel Trolley Rollers Wheel designed to handle loads up to 770 pounds, the sliding door rollers confidently supports heavy loads Color Silver (Pack of 4) Brand Name BiJun Manufacturer BiJun Material Type Stainless Steel Included Components NO