McMaster 30305T542 Samson Caster with 4 1 2" x 4" Mounting Plate, Swivel with Total Lock and 4" Diameter Phenolic Wheel 56732 They meet ASME specifications for They meet ASME specifications for rigging and lifting Part Circle Oil Fabrication Stamped Material Zinc Plated Steel Mount Type Plate Mounting Fasteners Included No Center to Center Length (A) 3 5 8" Center to Center Length (B) 3" Center to Center Width (A) 3" Center to Center Width (B) 2 5 8" Length 4 1 2" Width 4" Type Ball Seal Type Open Construction Dual Raceway Swivel Lock Activation Foot Pedal Tread Style Flat Wheel Tread Material Phenolic Country of Origin United States DFARS Compliance Specialty Metals COTS Exempt Export Control Classification Number (ECCN) EAR99 REACH Compliance Not Compliant RoHS Compliance RoHS 3 (2015 863 EU) Compliant Schedule B Number 871690 The wheels have roller bearings for smooth rolling