GGB has slider bearingsin different materials. Some are self-lubricating, others should be lubricated with oil or grease. The Metal-Polymer series are metal liners coated with PTFE or another plastic material.
DX should be lubricated with grease, while DU and DP4 are self-lubricating. These are the most affordable and widely used slider bearings.
Sintered metal and Bi-metal are sintered bronze with graphite. Bi-metal has a steel backing that allows for the creation of multiple varieties and dimensions.
Composite is woven fiberglass with PTFE. This is particularly suitable where there are humid environments and heavy loads.