no.. this is brand new.. but having experience with HET edf units.. I know I pushed their 70mm to the limits.. witha 4130kv hoffman magnetics the beast and 5s
I also know that they come balanced and they compare well to the wemos..their performance fihures are so identical but they work differently. the wemo though always has the edge but it costs far too much..
they don't have the whooshing sound but theyperform real well especially with higher kv motors and also won't give you tons of amp draw.
another plus is that you can find replacement parts.