Replacement black casters.  May be used to replace white casters on older steamers, but some drilling of the bottom plate is involved.  To avoid drilling, order part #0009.
 
Please note that Model J-2 steamers purchased after June 25, 2010, use the square plate, 2 hole caster (not the rectangular 4 hole plate).  Starting serial numbers for steamers with 2 hole casters:
120 volt J-2 serial number = T477401
230 volt J-2 serial number = T127211