These are Brushy Mt. feeders. They are floats. Personally, I'd cut some #8 hardware cloth and close the entrance down to just a 3/8" space coming into the syrup and running all the way to the bottom. That way the bees only have access to 3/8" of it and the floats are not necessary, there will be less drownings and you can refill without putting on a veil. If you don't want to do that, then just put in the floats and put on a veil when you refill and pour very slowly.