The deep inserts are black and the medium and shallow are white, each with a wax coating . Black is preferred for deeps because it is easier to see eggs with a black background. White is preferred for honey supers because it allows you to evaluate honey color better. We have heard much controversy about the virtues and vices of plastic . Getting the bees to pull plastic foundation is tough without wax . With a sufficient wax coating the bees have been known to pull it out even in a nectar dearth . The inserts we handle come waxed but more can be applied by dipping in wax or with a roller. Medium inserts can be used for shallow frames but will need to be cut down .