Steel

Expansion stem casters are designed to mount casters into open tubing fixtures. Turning of hex nut beneath the lower raceway on the caster expands the  rubber adapter inside of the round or square tubing for a tight fit. There are various stem sizes available which individually have a range of  tubing sizes the stem will fit into.

Cast Iron and Semi Steel Wheels are made of incredibly strong steel that is highly resistant to abuse and tough environments. Cast Iron wheels are able to withstand high temperatures and can be exposed to water and/or other abusive factors in challenging environments. They can withstand exposure to chemicals, grease and oil. However, one downside is that Cast Iron wheels will rust over time if exposed to fluids and chemicals regularly.