This is a shade for the luminescent panel-type nightlight so that it only illuminates the floor and doesn't shine light up into your eyes. I found this particularly useful in the bedroom so that I don't step on pets in the middle of the night, and my spouse doesn't complain about all the extra light on the walls and ceiling. It is also good for home theaters.

This is based on the 0.5 watt model HM-40 (written on back) light shown in the picture.

No supports required. Finish with some aluminum tape on the inside to retain efficiency, but not required. White plastic is fairly translucent so use a dark color if you don't want any stray light up into the room.