I just bought the 12C app for iPhone/iPad and one of these. I use them all, all day, every day. I'm an RPN addict and this calculator is just too cool for words. It's my little workhorse. Does it have a backspace key? No, it does not. Does it need one? It's an RPN calculator--are you joking? Is it programmable and does it do just about any financial calculation you can think of with ease? You better betcha buddy.