Pulse - SP

I was wondering what a pulse oximeter was when I read the description, then when I saw the pictures of one I knew exactly what it was. While I was at the hospital waiting to get my half off finger checked out, the nurse placed one on my finger, along with one of those blood pressure things. I really regret not asking the results of my blood pressure, must have nothing to worry about though as she never said anything about it, I'm sure she would have if it were bad.