Most plastic crates are manufactured from high density polyethylene (HDPE). Polyethylene offers good strength against impact (preventing breakage) and provides a high level of protection against degradation by ultraviolet radiation from sunlight. There are three typical designs for RPCs, and all three provide for ease of handling and protection of the produce. The first type is stackable, but not “nestable”, so empty crates take up the same amount of space as full crates. This type of design may increase the costs of returning empty crates, and so is used mostly for storage in systems where the RPCs remain within one facility and are reused each season. The second type is made to be nestable when empty, and the third type is designed to be collapsible when empty. Both of these designs will help reduce the transport costs associated with empty RPC returns.