At the National Honey Show in the UK I bought some National and Langstroth Frames to go in Nuc boxes which do both sizes - Thanks to the nice ladies at Mann Lake, I can now use the boxes as Langstroth or National.
I had bought some Waxed Lang Cardboard Nuc boxes with a view to catching stray swarms next year, but fully aware some Beeks, nay most here in the UK use National Frames which are about 2"(5cm) shorter than the Langs in the top bar and nearly 4"(10cm) shorter in the body.
The Boxes are Lang to fit Lang sized Fames but a nifty bit of Cardboard comes with he purchase of the “National” option which is a Lange box effectively with a National converter cardboard insert.
Having made up Lang frames quite quickly and then sitting down to a pile (50 flat frames bought) of 20 National Frames to make up, I don’t know how the Poms put up with Nationals - They are so Fiddly to make up compared to the Langs, and the Langstroth Frames Support more Cells per frames so Win win