suitable for KS3 +. Ray Box - All metal Ventilated Lamp House with an open front and extended sides finned externally for heat dissipation and vertical internal grooves to accommodate a slit plate and cylindrical lens. 12 volts lamp and one meter twin flex with plugs. Complete with slit plate with single and triple slits. Spares available; Plano Convex Lens (Code 0326), Spare Slit Plate (Code 0329), Spare Bulb (Code 0327), Bulb Holder (Code 0328), Bulb Holder with Flex (Code 0564).