A garden edging system is made up of one or more straight edger units, one or more curved edger units and one or more corner units. The apparatus comprises an area in which said device is to be heated and inlet means adapted to supply a relatively inert gas to the said area. The spring plate is mounted on the bottom wall of the shell and has a main portion and a number of elastic arms extending outward from the two opposite sides of the main portion. Each MEMS element imparts an optical effect, such as angular change, on the output beam. The light guide can be used with reflectors that have originally been manufactured for use with high intensity discharge lamps or halogen lamps but because of the light guide, the reflectors can be used together with light sources in the form of at least one light emitting diode.