You're viewing caster SKU 6-82-539-7 on CasterConnection.com.
This 6 x 2 Glass-Filled Nylon Rigid Caster offers the same weight capacity as a steel wheel but is dramatically lighter and wont rust. They have an operating temperature of -45° to +350° Fahrenheit. Glass filled nylon wheels have good abrasion and compression resistance and they wont flat spot.
For more info, check out Caster Wheel Types.