Understanding and managing varroa are critical components to sustainable beekeeping. Varroa awareness and management is the main reason I've been able to successfully overwinter nearly 80% of my colonies in the last 3 years.
Yes, I watched a long video on this. If I used wooden gear, I'd try to build or buy something like this. But in Alaska, my bees benefit from insulation year round, and this type of system isn't designed to be removed and re-installed during inspections. Research shows insulated hives produce more wax, more brood, and more honey - which mostly occur during periods when this device wouldn't be on the hive. I have big problem with the design - it should eliminate the wooden inner cover. Replacing it with Reflectix ensures no upper heat loss (the wood bleeds heat all winter).