Ron Kulva knows the trouble you're in trying to keep that thing alive.

"One year I was crawling under the tree to check the water level," he says. "You know how you crawl under and stick your finger in the thing? And I got poked in the eye.

"I just got tired of it."

The first EZ Filler -- an automatic Christmas tree stand filler made of plexiglass -- soon followed.

The current version -- an 8-by-8-by-8-inch polyethylene cube ("you can have any color as long as it's red") with a vinyl hose that siphons the water from cube to tree -- is selling by mail order for $9.99 out of Kulva's College Park home (4900 Nantucket Rd., 20740) The car no longer fits in his overstuffed garage, but what price fortune?

Actually, Kulva, who has a day job as an engineer, sounds as excited about the benefits of the EZ Filler as he is about his budding business. "Now I can check the water level without crawling under the tree . . . It works great for tree preservatives. And the reason that we made it a cube is so that it can be wrapped up like a present."

It's better than a sharp stick in the eye.