These are flat-packed Brood/Deep British National frames with gimp pins. They are self spacing and mostly used in British National, WBC and similarly sized beehives.The frames are A grade quality and can be used mixed with DN1 frames if plastic spacers are also used.These are the national brood frames with DN4 top bar. Visit us- https://www.apisbeesupplies.ie/frames-and-foundation read full review »