These inserts have been manufactured from zinc galvanised steel. The process of galvanisation adds a coat of zinc to the steel, which will help improve its resistance against corrosion caused by both the atmosphere and the elements. The insert has been designed to slot into the top of the planter, acting as a shelf that will reduce its internal volume so that it can be used to display smaller plants. Due to the way it has been constructed, this insert can also be used as a planter on its own.