What Racquet did Del Porto use between 2009-2014?

I know there's been a few discussions similar to this but I've not come across any clear answers. Many have said he used a pro staff classic 6.1 under a k- factor pj?And previous to that he used a hyper pro staff?

was it the k -factor he used when he won US open in 09?
Also would be curious to know what he uses today?

Any info and opinions would be much appreciated.