When I started working in the pest control industry I was taught how to make exclusion tunnels out of 1" x 2" wire fencing. That is the industry standard way it has always been done and for lack of something better that is the way everyone does it. Over time I tried to tweak the way I made them to cut down on the number of return visits due to squirrels getting past my tunnels because they were smaller than the fencing space or sometimes so fat that when they squeezed out the spikes would bend open leaving the end big enough for them to get back in. Also over time I have had the chance to be called to a job because the previous pest control company could not stop the squirrels and I have found so many variations and styles of homemade tunnels that failed to give the proper results.
Based on all that experience I set off to create a tunnel that was quick to make, easy to install and would yield results far better than anything home made, the Squirrel Rocket is the result. It's dimensions are based on the size of the homemade wire fencing tunnels I had the most success with. The sheet material allows for closed sides so smaller squirrels and birds and bats can't avoid the spikes and sneak in through the sides and the very sharp spikes on the end are much more uncomfortable than just the four or five prongs of wire material left sticking off the end of a homemade tunnel.
After it was made I set off testing it in my own wildlife control business and was so happy with the results. Call backs dropped to an all time low. I have installed about 600 of these tunnels and they simply work. No problems with my guys making tunnels too big or spending time making tunnels out in the field. In less than a minute the tunnel is ready to be installed.