As a newbie agent back in the dark ages, I remember going to an Open House and seeing two older agents packing up to go home, and they had two tomes that contained formulas for calculating monthly mortgage payments, each weighing about 20-pounds. I felt very smug, because I had a handy little HP financial calculator about twice the size of my iPhone in my pocket. Karl takes it a stop further, putting a very simple to use app out there for your smart phone. While there are lots of financial apps out there, this one is just a no-brainer simple one that passes the geezer test.