These items are small 60mm diameter balls that, when tapped, light up. Their soft white light fills an area as large as 5×5×5 meters and if left will last 30 days. Further taps turn them off and on. They can also serve as wireless repeaters to enhance the PDA messaging range. A small flat area on one side is covered in smart glue so that the glow ball can be hung on a wall or ceiling. Their weight is less than 20 grams, and they cost Cr10. An infrared version exists that provides heat instead of visible light. They last only 20 days and cost the same amount.