This is what I use. It does not get 100% of the oil out but it is good for changing the oil in the field and you don't have time to change filters and drain it completley.
You can order and install the Drainzit hoses that have caps on them for draining the oil, they are about $19.99 for most engines and pumps, you see hoses hanging from engines and pumps on rigs, those are the Drainzit or home-made versions. In case you wanted to try them, they do work good.