Alex brought over a unit a friend loaned him (and didn't want back) 

after he hurt his knee snowboarding into a tree.  

Basically you put ice into the cooler and wrap the pads around the knee.  Then the tube sends a flow of cold air around the knee.  I used the apparatus for an hour, and it helped some.

But what really helped was taking 600 units of Rx ibuprofen.

My pain is in Area D - where arthritis is one of the causes.