I saw it in one of the YouTube videos on catching swarms. It looks like a round plastic item, 6" diameter (?) with a screw hole in the middle so it can rotate. I think it has four positions: full open, queen excluder mesh, vent only for transport and I am not sure on the last one. It sits over a round hole on the front of the NUC and rotates so you can select your desired opening. I think the one I saw was green. I am getting ready to make some NUCs and would like to buy some. Please who has them for sale?
Thanks in advance.