12x4 HEAVY DUTY PNEUMATIC SWIVEL CASTER - Allied Caster
CasterHQ 10" x 3.5" Swivel of 4 Set Pneumatic Caster - 4 PLY - 350 LBS PER 1400 LBS PER Set Capacity - Air Filled - Commercial/Industrial Application 10 inch x 3.5 inch Shock Absorption: Amazon.com: Industrial & Scientific
15,000-pound capacity pneumatic swivel caster with swivel lock - Material Handling 24/7