Here you see a model of ATP-dependent processive cleavage of long dsRNA by Dicer. Substrate recognition is not depicted accurately but energy-dependent enzyme's processivity and production of small RNA duplexes of one size is captured well. Note also premature product unwinding.
I've run Bobcats many times and worked around them even more. There are several attachments you can put on the front of them, but this has to be the most handy and baddass thing there is. After cutting it into manageable lengths she pushes it through an X splitter. So damn cool.