Detailed Size and Load Capacity: steel plate aperture 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 taller strut channels; Single 4 wheel trolley assembly can hold up to 450 lbs Heavy Duty: trolley assembly is made of strengthened solid steel and galvanized properties, sturdy and reliable, impact resistance, smooth and noiseless, hard to break, deform, fade, rust and corrosion, withstand long term use Versatile to Use: the chain hoist 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 Get: the package comes with 4 pieces of beam trolleys assembly, which can withstand a certain heavy load, to meet your using and replacement needs, bringing a lot of convenience to life Stable Performance: 4 Pcs bearing trolley channel roller with welded bearings and pin shaft is safe and reliable, with tight connection and stable performance can ensure smooth 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.