It's very similar to Certan B401 but an awful lot less expensive and works the same way ... used correctly on stored frames it stops wax moth damage by killing the larvae - no harm to the bees at all when you re-use the frames and no apparent resistance from the bees from putting brood into the cells. If there was a problem the bees would be sensitive to it. As I sadi earlier, I have used it over two winters now with total success.
