This is a square plastic light base, 6 cm wide, 6 cm deep and 3 cm high. In the middle of the top, an LED glows in colour under a small clear dome. It is made to sit under a laser-etched glass block, the kind with a picture or words engraved inside the glass. You get one base, without a glass block and without a battery. Made in China.
Light from below for the etched picture
Inside the glass block, the picture is made of tiny white dots. In daylight they look faint and are often hard to see. Stand the block on this base and the LED shines up through the glass, so the dots light up. It looks best in the evening, in a dimly lit room: the darker the room, the more clearly the dots stand out from the glass.
What size of block fits?
The top of the base is 6 × 6 cm. It suits a glass block whose bottom is the same size or a little smaller. A larger block would overhang the edges and tip over more easily. Before you order, measure the bottom of your block with a ruler. The base weighs under 50 g, so put it on a flat, steady surface such as a chest of drawers, a glass cabinet or a bedside table. Do not stand a glass ball on it, as it could roll off the small dome in the middle.
Battery and switch
There is a small switch on the side to turn the light on and off. It runs on a battery, so you do not need a socket nearby. The battery is not in the box, so you will need to buy one. If you are not going to use it for a few weeks, take the battery out.
Perhaps you have a photo glass block that was a present and has only ever stood in a cabinet. On this base you can see the picture inside it in the evening too.