I can see a lot of uses for these boxes. For me, they would allow me to continue to uncap while my extractor was spinning. I have always been disappointed that Mann Lake's plastic uncapping tank would not accommodate frames. A couple of these boxes and you could uncap up to 20 frames while your extractor was spinning. They are a bit pricey, but cheaper than the uncapping tanks that are actually designed to hold frames.
Does anyone have any experience with the Hive Butler boxes?