Product review (3 stars): It is what it is, but narrower...
I get these vinyl hoses as toys for my ferrets.  They were narrower than 4" at different points in the hose, but I've ordered more than one and they come the same.  Not important if you're using it for air.

Price was okay considering these vinyl hoses are being phased out for the aluminum ones (*not* good for ferret tunnels), shipping was fast.