Caster and wheels are often categorized by their weight handling ability, these categories are simply "Light Duty, Medium Duty, Heavy Duty and Super Duty. To lessen confusion we will define these caster categories to better help you find what you are looking for.
Light Duty, Dolly Caster, XS Rubber wheel, rigidThe light duty category of casters and wheels specifications are as follows. Wheel size; diameter of the wheel is usually between 2" and 5" with a tread width of 7/8" to 1-1/2". The load capacity of Light duty casters is up to roughly 400lbs per caster. So as you can see the "Light duty" can still be very strong and substantial.
Typical applications for Light Duty stem or plate mount casters in swivel or rigid would be: Medical equipment, dollies, office chairs, computer carts, Displays and fixtures, Rubbermaid carts and mop buckets, etc. Any cart that has 4 casters and is under 1200lb would qualify as light duty. Usually Rubber, plastic or Polyurethane wheel material.