OK no laughing now and I know they have some that are factory built, but what I have made is a soup can with a small mushroom can stacked inside it. It is held up by four small screws just high enough where aunscented candle flame heats up the deer scent inside. 1 candle and a 50/50 mix of your favorite scent and water will last about four hours. It vaporizes the scent. You have to drill a few small holes in the flame can to get air to it or the candlewill not burn. Works for me. Last year it pulled a really nice buck away from a doeabout 200 yards away. Pretty much put him in my lap for a easy shot.