From Gardener's Supply (

By day, these are delightful window decorations; by night (and with the flip of a switch) they glow — a beautiful way to light up a window, inside and out. Set includes five different snowflakes. Suction cups on the back lets you attach them to any smooth surface. There are no wires, so the snowflakes appear suspended in mid-air. May also be hung with monofilament line. Each snowflake is lit by one LED.