If those are the Wagner Lighting H6006 unit they are no longer made. they stopped production in 2009. You can find them on the bay or if your lucky at a long time local parts store. My local store had 24 on the shelf in March at $8.99 ea. Then 0 a month later.
Henry, if you are running w/stock 6-volt system, the generator is able to keep up? I heard these lights tax generator output. Steve