Detailed Size and Load Capacity: steel plate is 9/16 inch/ 14 mm, thickness is about 2/5 inch/ 10 mm, suitable for 1-5/8 inch wide and all 1-5/8 inch or strut channels; Single 4 wheel trolley assembly can to 450 lbs Heavy Duty: trolley assembly is made of strengthened solid steel and galvanized properties, sturdy and , impact resistance, and noiseless, hard to break, deform, fade, rust and corrosion, withstand long term use Versatile to Use: the chain trolley wheel is suitable for a wide range of different usage scenarios and is perfect for mounting on a ceiling trolley system or electric lifts, you can also use it in DIY projects according to your actual situation What You Will : the package comes with 4 pieces of beam assembly, which can withstand a certain , to meet your using and replacement needs, bringing a lot of to life Stable Performance: 4 Pcs bearing trolley channel roller with welded bearings and pin shaft is safe and , with tight connection and stable performance can operation and reduce noise color:Silver Material:steel size:91 x 59 x 96mm Package Contents: 4 x trolley Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.